diff --git a/examples/validations/src/bashly.yml b/examples/validations/src/bashly.yml
index 93790b65..db0e83e0 100644
--- a/examples/validations/src/bashly.yml
+++ b/examples/validations/src/bashly.yml
@@ -15,9 +15,12 @@ commands:
     # Bashly will look for a function named `validate_integer` in your
     # script, you can use any name as long as it has a matching function.
     validate: integer
+  
   - name: second
     help: Second number
-    validate: integer
+
+    # Multiple validations can be provided as an array.
+    validate: [not_empty, integer]
 
   flags:
   - long: --save
diff --git a/examples/validations/test.sh b/examples/validations/test.sh
index f7eb8769..41f87490 100644
--- a/examples/validations/test.sh
+++ b/examples/validations/test.sh
@@ -12,6 +12,7 @@ bashly generate
 
 ./validate calc 1 2 --save README.md
 ./validate calc A
+./validate calc 1 ''
 ./validate calc 1 B
 ./validate calc 1 2 --save no-such-file.txt
 
diff --git a/lib/bashly.rb b/lib/bashly.rb
index 016e2e2d..a934b5c1 100644
--- a/lib/bashly.rb
+++ b/lib/bashly.rb
@@ -28,7 +28,7 @@ module Script
     module Introspection
       autoloads 'bashly/script/introspection', %i[
         Arguments Commands Dependencies EnvironmentVariables Examples Flags
-        Variables Visibility
+        Validate Variables Visibility
       ]
     end
   end
diff --git a/lib/bashly/config_validator.rb b/lib/bashly/config_validator.rb
index 650a5eb6..0c430054 100644
--- a/lib/bashly/config_validator.rb
+++ b/lib/bashly/config_validator.rb
@@ -92,7 +92,7 @@ def assert_arg(key, value)
       assert_string "#{key}.name", value['name']
       assert_optional_string "#{key}.help", value['help']
       assert_string_or_array "#{key}.default", value['default']
-      assert_optional_string "#{key}.validate", value['validate']
+      assert_string_or_array "#{key}.validate", value['validate']
       assert_boolean "#{key}.required", value['required']
       assert_boolean "#{key}.repeatable", value['repeatable']
       assert_boolean "#{key}.unique", value['unique']
@@ -123,7 +123,7 @@ def assert_flag(key, value)
       assert_optional_string "#{key}.help", value['help']
       assert_optional_string "#{key}.arg", value['arg']
       assert_string_or_array "#{key}.default", value['default']
-      assert_optional_string "#{key}.validate", value['validate']
+      assert_string_or_array "#{key}.validate", value['validate']
 
       assert_boolean "#{key}.private", value['private']
       assert_boolean "#{key}.repeatable", value['repeatable']
@@ -169,7 +169,7 @@ def assert_env_var(key, value)
       assert_boolean "#{key}.required", value['required']
       assert_boolean "#{key}.private", value['private']
       assert_array "#{key}.allowed", value['allowed'], of: :string
-      assert_optional_string "#{key}.validate", value['validate']
+      assert_string_or_array "#{key}.validate", value['validate']
 
       refute value['required'] && value['default'], "#{key} cannot have both nub`required` and nub`default`"
     end
diff --git a/lib/bashly/script/argument.rb b/lib/bashly/script/argument.rb
index cb18fe79..5fd96f6e 100644
--- a/lib/bashly/script/argument.rb
+++ b/lib/bashly/script/argument.rb
@@ -3,6 +3,8 @@
 module Bashly
   module Script
     class Argument < Base
+      include Introspection::Validate
+
       class << self
         def option_keys
           @option_keys ||= %i[
diff --git a/lib/bashly/script/command.rb b/lib/bashly/script/command.rb
index ba20bb00..7b109c0a 100644
--- a/lib/bashly/script/command.rb
+++ b/lib/bashly/script/command.rb
@@ -158,7 +158,7 @@ def user_lib
 
       # Returns a mixed array of Argument and Flag objects that have validations
       def validatables
-        @validatables ||= args.select(&:validate) + flags.select(&:validate)
+        @validatables ||= args.select(&:validate?) + flags.select(&:validate?)
       end
 
     private
diff --git a/lib/bashly/script/environment_variable.rb b/lib/bashly/script/environment_variable.rb
index 4e3b08b7..97a1d3ed 100644
--- a/lib/bashly/script/environment_variable.rb
+++ b/lib/bashly/script/environment_variable.rb
@@ -2,6 +2,7 @@ module Bashly
   module Script
     class EnvironmentVariable < Base
       include Introspection::Visibility
+      include Introspection::Validate
 
       class << self
         def option_keys
diff --git a/lib/bashly/script/flag.rb b/lib/bashly/script/flag.rb
index 2d5bc048..19fca03f 100644
--- a/lib/bashly/script/flag.rb
+++ b/lib/bashly/script/flag.rb
@@ -5,6 +5,7 @@ module Script
     class Flag < Base
       include Completions::Flag
       include Introspection::Visibility
+      include Introspection::Validate
 
       class << self
         def option_keys
diff --git a/lib/bashly/script/introspection/environment_variables.rb b/lib/bashly/script/introspection/environment_variables.rb
index 502be4bb..04476919 100644
--- a/lib/bashly/script/introspection/environment_variables.rb
+++ b/lib/bashly/script/introspection/environment_variables.rb
@@ -28,7 +28,7 @@ def required_environment_variables
 
         # Returns an array of all the environment_variables with a validation
         def validated_environment_variables
-          environment_variables.select(&:validate)
+          environment_variables.select(&:validate?)
         end
 
         # Returns only public environment variables, or both public and private
diff --git a/lib/bashly/script/introspection/validate.rb b/lib/bashly/script/introspection/validate.rb
new file mode 100644
index 00000000..8550bde0
--- /dev/null
+++ b/lib/bashly/script/introspection/validate.rb
@@ -0,0 +1,18 @@
+module Bashly
+  module Script
+    module Introspection
+      module Validate
+        # Returns an array of validations
+        def validate
+          return [] unless options['validate']
+
+          result = options['validate']
+          result.is_a?(Array) ? result : [result]
+        end
+
+        # Returns true if there are any validations defined
+        def validate? = validate.any?
+      end
+    end
+  end
+end
diff --git a/lib/bashly/views/argument/validations.gtx b/lib/bashly/views/argument/validations.gtx
index 758217ab..d2b7e910 100644
--- a/lib/bashly/views/argument/validations.gtx
+++ b/lib/bashly/views/argument/validations.gtx
@@ -1,4 +1,4 @@
-if validate
+if validate?
   = view_marker
 
   if repeatable
@@ -6,20 +6,24 @@ if validate
     >   values=''
     >   eval "values=(${args['{{ name }}']})"
     >   for value in "${values[@]}"; do
-    >     validation_output="$(validate_{{ validate }} "$value")"
+    validate.each do |funcname|
+    >     validation_output="$(validate_{{ funcname }} "$value")"
     >     if [[ -n "$validation_output" ]]; then
     >       printf "{{ strings[:validation_error] }}\n" "{{ name.upcase }}" "$validation_output" >&2
     >       exit 1
     >     fi
+    end
     >   done
     > fi
   else
     > if [[ -v args['{{ name }}'] ]]; then
-    >   validation_output="$(validate_{{ validate }} "${args['{{ name }}']:-}")"
+    validate.each do |funcname|
+    >   validation_output="$(validate_{{ funcname }} "${args['{{ name }}']:-}")"
     >   if [[ -n "$validation_output" ]]; then
     >     printf "{{ strings[:validation_error] }}\n" "{{ name.upcase }}" "$validation_output" >&2
     >     exit 1
     >   fi
+    end
     > fi
     >
   end
diff --git a/lib/bashly/views/environment_variable/validations.gtx b/lib/bashly/views/environment_variable/validations.gtx
index abbf1ebc..578eef91 100644
--- a/lib/bashly/views/environment_variable/validations.gtx
+++ b/lib/bashly/views/environment_variable/validations.gtx
@@ -1,12 +1,14 @@
-if validate
+if validate?
   = view_marker
 
   > if [[ -v {{ name.upcase }} ]]; then
-  >   validation_output="$(validate_{{ validate }} "${{ name.upcase }}")"
+  validate.each do |funcname|
+  >   validation_output="$(validate_{{ funcname }} "${{ name.upcase }}")"
   >   if [[ -n "${validation_output}" ]]; then
   >     printf "{{ strings[:environment_variable_validation_error] }}\n" "{{ usage_string }}" "$validation_output" >&2
   >     exit 1
   >   fi
+  end
   > fi
   >
 end
diff --git a/lib/bashly/views/flag/validations.gtx b/lib/bashly/views/flag/validations.gtx
index 43b0628a..06665323 100644
--- a/lib/bashly/views/flag/validations.gtx
+++ b/lib/bashly/views/flag/validations.gtx
@@ -1,4 +1,4 @@
-if validate
+if validate?
   = view_marker
 
   if repeatable
@@ -6,20 +6,24 @@ if validate
     >   values=''
     >   eval "values=(${args['{{ long }}']})"
     >   for value in "${values[@]}"; do
-    >     validation_output="$(validate_{{ validate }} "$value")"
+    validate.each do |funcname|
+    >     validation_output="$(validate_{{ funcname }} "$value")"
     >     if [[ -n "$validation_output" ]]; then
     >       printf "{{ strings[:validation_error] }}\n" "{{ usage_string }}" "$validation_output" >&2
     >       exit 1
     >     fi
     >   done
+    end
     > fi
   else
     > if [[ -v args['{{ long }}'] ]]; then
-    >   validation_output="$(validate_{{ validate }} "${args['{{ long }}']:-}")"
+    validate.each do |funcname|
+    >   validation_output="$(validate_{{ funcname }} "${args['{{ long }}']:-}")"
     >   if [[ -n "${validation_output}" ]]; then
     >     printf "{{ strings[:validation_error] }}\n" "{{ usage_string }}" "$validation_output" >&2
     >     exit 1
     >   fi
+    end
     > fi
     >
   end
diff --git a/schemas/bashly.json b/schemas/bashly.json
index 0c0160fe..06615873 100644
--- a/schemas/bashly.json
+++ b/schemas/bashly.json
@@ -76,12 +76,27 @@
         "validate": {
           "title": "validate",
           "description": "A validation function of the current positional argument\nhttps://bashly.dev/configuration/argument/#validate",
-          "type": "string",
+          "oneOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "array",
+              "minItems": 1,
+              "items": {
+                "type": "string"
+              }
+            }
+          ],
           "examples": [
             "file_exists",
             "dir_exists",
             "integer",
-            "non_empty"
+            "non_empty",
+            [
+              "file_exists",
+              "file_writable"
+            ]
           ]
         },
         "unique": {
@@ -261,12 +276,27 @@
         "validate": {
           "title": "validate",
           "description": "A validation function of the current flag\nhttps://bashly.dev/configuration/flag/#validate",
-          "type": "string",
+          "oneOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "array",
+              "minItems": 1,
+              "items": {
+                "type": "string"
+              }
+            }
+          ],
           "examples": [
             "file_exists",
             "dir_exists",
             "integer",
-            "non_empty"
+            "non_empty",
+            [
+              "file_exists",
+              "file_writable"
+            ]
           ]
         },
         "unique": {
@@ -337,12 +367,27 @@
         "validate": {
           "title": "validate",
           "description": "A validation function for the current environment variable\nhttps://bashly.dev/configuration/environment-variable/#validate",
-          "type": "string",
+          "oneOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "array",
+              "minItems": 1,
+              "items": {
+                "type": "string"
+              }
+            }
+          ],
           "examples": [
             "file_exists",
             "dir_exists",
             "integer",
-            "non_empty"
+            "non_empty",
+            [
+              "file_exists",
+              "file_writable"
+            ]
           ]
         },
         "allowed": {
diff --git a/spec/approvals/examples/validations b/spec/approvals/examples/validations
index 77d3d534..22966367 100644
--- a/spec/approvals/examples/validations
+++ b/spec/approvals/examples/validations
@@ -22,6 +22,9 @@ args:
 + ./validate calc A
 validation error in FIRST:
 must be an integer
++ ./validate calc 1 ''
+validation error in SECOND:
+must not be empty
 + ./validate calc 1 B
 validation error in SECOND:
 must be an integer
diff --git a/spec/bashly/commands/preview_spec.rb b/spec/bashly/commands/preview_spec.rb
index 6839888f..3246f417 100644
--- a/spec/bashly/commands/preview_spec.rb
+++ b/spec/bashly/commands/preview_spec.rb
@@ -21,5 +21,3 @@
     end
   end
 end
-
-
diff --git a/spec/bashly/integration/examples_spec.rb b/spec/bashly/integration/examples_spec.rb
index 690bd598..6285fc1a 100644
--- a/spec/bashly/integration/examples_spec.rb
+++ b/spec/bashly/integration/examples_spec.rb
@@ -24,10 +24,10 @@
   # Allow up to a certain string distance from the approval text in CI
   leeway = ENV['CI'] ? 40 : 0
 
-  # For certain examples, allow some exceptions (replacements) since they 
+  # For certain examples, allow some exceptions (replacements) since they
   # are too volatile (e.g. line number changes)
   exceptions = {
-    'examples/stacktrace' => [/download:\d+/, 'download:<line>'],
+    'examples/stacktrace'    => [/download:\d+/, 'download:<line>'],
     'examples/render-mandoc' => [/Version 0.1.0.*download\(1\)/, '<footer>'],
   }
 
diff --git a/spec/bashly/script/argument_spec.rb b/spec/bashly/script/argument_spec.rb
index 8d1bb973..cea09a69 100644
--- a/spec/bashly/script/argument_spec.rb
+++ b/spec/bashly/script/argument_spec.rb
@@ -6,6 +6,13 @@
 
   let(:fixture) { :basic_argument }
 
+  describe 'composition' do
+    it 'includes the necessary modules' do
+      modules = [Script::Introspection::Validate]
+      expect(described_class.ancestors).to include(*modules)
+    end
+  end
+
   describe '#default_string' do
     context 'when default is an array' do
       let(:fixture) { :default_array }
diff --git a/spec/bashly/script/command_spec.rb b/spec/bashly/script/command_spec.rb
index f7d3adce..df84b888 100644
--- a/spec/bashly/script/command_spec.rb
+++ b/spec/bashly/script/command_spec.rb
@@ -8,6 +8,23 @@
   let(:fixtures) { load_fixture 'script/commands' }
   let(:fixture) { :basic_command }
 
+  describe 'composition' do
+    it 'includes the necessary modules' do
+      modules = [
+        Script::Introspection::Arguments,
+        Script::Introspection::Commands,
+        Script::Introspection::Dependencies,
+        Script::Introspection::EnvironmentVariables,
+        Script::Introspection::Examples,
+        Script::Introspection::Flags,
+        Script::Introspection::Variables,
+        Script::Introspection::Visibility,
+        Completions::Command,
+      ]
+      expect(described_class.ancestors).to include(*modules)
+    end
+  end
+
   describe '#action_name' do
     context 'when it is the root command' do
       it 'returns root' do
diff --git a/spec/bashly/script/environment_variable_spec.rb b/spec/bashly/script/environment_variable_spec.rb
new file mode 100644
index 00000000..a11652da
--- /dev/null
+++ b/spec/bashly/script/environment_variable_spec.rb
@@ -0,0 +1,37 @@
+describe Script::EnvironmentVariable do
+  subject do
+    options = load_fixture('script/env_vars')[fixture]
+    described_class.new options
+  end
+
+  let(:fixture) { :basic_env_var }
+
+  describe 'composition' do
+    it 'includes the necessary modules' do
+      modules = [Script::Introspection::Visibility, Script::Introspection::Validate]
+      expect(described_class.ancestors).to include(*modules)
+    end
+  end
+
+  describe '#usage_string' do
+    it 'returns a string suitable to be used as a usage pattern' do
+      expect(subject.usage_string).to eq 'BUILD_DIR'
+    end
+
+    context 'with extended: true' do
+      context 'when the flag is optional' do
+        it 'returns the same string as it does without extended' do
+          expect(subject.usage_string(extended: true)).to eq subject.usage_string
+        end
+      end
+
+      context 'when the flag is also required' do
+        let(:fixture) { :required }
+
+        it 'appends (required) to the usage string' do
+          expect(subject.usage_string(extended: true)).to eq "#{subject.usage_string} (required)"
+        end
+      end
+    end
+  end
+end
diff --git a/spec/bashly/script/flag_spec.rb b/spec/bashly/script/flag_spec.rb
index 90b7b216..bce2f523 100644
--- a/spec/bashly/script/flag_spec.rb
+++ b/spec/bashly/script/flag_spec.rb
@@ -6,6 +6,16 @@
 
   let(:fixture) { :basic_flag }
 
+  describe 'composition' do
+    it 'includes the necessary modules' do
+      modules = [
+        Script::Introspection::Visibility, Script::Introspection::Validate,
+        Completions::Flag
+      ]
+      expect(described_class.ancestors).to include(*modules)
+    end
+  end
+
   describe '#aliases' do
     context 'with long and short options' do
       it 'returns an array of both long and short values' do
diff --git a/spec/bashly/script/introspection/validate_spec.rb b/spec/bashly/script/introspection/validate_spec.rb
new file mode 100644
index 00000000..610d1898
--- /dev/null
+++ b/spec/bashly/script/introspection/validate_spec.rb
@@ -0,0 +1,40 @@
+describe Script::Introspection::Validate do
+  subject do
+    Script::Flag.new fixtures[fixture]
+  end
+
+  let(:fixtures) { load_fixture 'script/arguments' }
+  let(:fixture) { :basic_argument }
+
+  describe '#validate' do
+    context 'with a string value' do
+      let(:fixture) { :validate_string }
+
+      it 'returns it as an array' do
+        expect(subject.validate).to eq ['file_exists']
+      end
+    end
+
+    context 'with an array value' do
+      let(:fixture) { :validate_array }
+
+      it 'returns it as is' do
+        expect(subject.validate).to eq %w[file_exists file_is_writable]
+      end
+    end
+  end
+
+  describe '#validate?' do
+    it 'returns false' do
+      expect(subject.validate?).to be false
+    end
+
+    context 'when validations are defined' do
+      let(:fixture) { :validate_string }
+
+      it 'returns true' do
+        expect(subject.validate?).to be true
+      end
+    end
+  end
+end
diff --git a/spec/fixtures/script/arguments.yml b/spec/fixtures/script/arguments.yml
index 67f0a3a9..b5dc1143 100644
--- a/spec/fixtures/script/arguments.yml
+++ b/spec/fixtures/script/arguments.yml
@@ -23,3 +23,11 @@
   name: file
   repeatable: true
   default: spaced one
+
+:validate_string:
+  name: file
+  validate: file_exists
+
+:validate_array:
+  name: file
+  validate: [file_exists, file_is_writable]
diff --git a/spec/fixtures/script/env_vars.yml b/spec/fixtures/script/env_vars.yml
new file mode 100644
index 00000000..1abe7e82
--- /dev/null
+++ b/spec/fixtures/script/env_vars.yml
@@ -0,0 +1,14 @@
+:basic_env_var:
+  name: build_dir
+
+:required:
+  name: build_dir
+  required: true
+
+:validate_string:
+  name: build_dir
+  validate: dir_exists
+
+:validate_array:
+  name: build_dir
+  validate: [dir_exists, dir_is_writable]
diff --git a/spec/fixtures/script/flags.yml b/spec/fixtures/script/flags.yml
index e0de14e6..1346ab31 100644
--- a/spec/fixtures/script/flags.yml
+++ b/spec/fixtures/script/flags.yml
@@ -44,3 +44,13 @@
   arg: path
   repeatable: true
   default: spaced one
+
+:validate_string:
+  long: --file
+  arg: name
+  validate: file_exists
+
+:validate_array:
+  long: --file
+  arg: name
+  validate: [file_exists, file_is_writable]
diff --git a/support/schema/bashly.yml b/support/schema/bashly.yml
index 251f8aea..b27a0403 100644
--- a/support/schema/bashly.yml
+++ b/support/schema/bashly.yml
@@ -73,12 +73,18 @@ definitions:
         description: |-
           A validation function of the current positional argument
           https://bashly.dev/configuration/argument/#validate
-        type: string
+        oneOf:
+          - type: string
+          - type: array
+            minItems: 1
+            items:
+              type: string
         examples:
           - file_exists
           - dir_exists
           - integer
           - non_empty
+          - [file_exists, file_writable]
       unique:
         title: unique
         description: |-
@@ -239,12 +245,18 @@ definitions:
         description: |-
           A validation function of the current flag
           https://bashly.dev/configuration/flag/#validate
-        type: string
+        oneOf:
+          - type: string
+          - type: array
+            minItems: 1
+            items:
+              type: string
         examples:
           - file_exists
           - dir_exists
           - integer
           - non_empty
+          - [file_exists, file_writable]
       unique:
         title: unique
         description: |-
@@ -305,12 +317,18 @@ definitions:
         description: |-
           A validation function for the current environment variable
           https://bashly.dev/configuration/environment-variable/#validate
-        type: string
+        oneOf:
+          - type: string
+          - type: array
+            minItems: 1
+            items:
+              type: string
         examples:
           - file_exists
           - dir_exists
           - integer
           - non_empty
+          - [file_exists, file_writable]
       allowed:
         title: allowed
         description: |-