diff --git a/lib/super_diff/active_record/inspection_tree_builders/active_record_model.rb b/lib/super_diff/active_record/inspection_tree_builders/active_record_model.rb
index 25bf2a2c..17582508 100644
--- a/lib/super_diff/active_record/inspection_tree_builders/active_record_model.rb
+++ b/lib/super_diff/active_record/inspection_tree_builders/active_record_model.rb
@@ -6,6 +6,10 @@ def self.applies_to?(value)
           value.is_a?(::ActiveRecord::Base)
         end
 
+        def id
+          object.class.primary_key
+        end
+
         def call
           Core::InspectionTree.new do |t1|
             t1.as_lines_when_rendering_to_lines(
@@ -21,7 +25,7 @@ def call
 
             t1.nested do |t2|
               t2.insert_separated_list(
-                ["id"] + (object.attributes.keys.sort - ["id"])
+                [id] + (object.attributes.keys.sort - [id])
               ) do |t3, name|
                 t3.as_prefix_when_rendering_to_lines do |t4|
                   t4.add_text "#{name}: "
diff --git a/lib/super_diff/active_record/monkey_patches.rb b/lib/super_diff/active_record/monkey_patches.rb
index b2ebce7e..52ae6634 100644
--- a/lib/super_diff/active_record/monkey_patches.rb
+++ b/lib/super_diff/active_record/monkey_patches.rb
@@ -2,9 +2,11 @@
 class ActiveRecord::Base
   # TODO: Remove this monkey patch if possible
   def attributes_for_super_diff
-    (attributes.keys.sort - ["id"]).reduce({ id: id }) do |hash, key|
-      hash.merge(key.to_sym => attributes[key])
-    end
+    id_attr = self.class.primary_key
+
+    (attributes.keys.sort - [id_attr]).reduce(
+      { id_attr.to_sym => id }
+    ) { |hash, key| hash.merge(key.to_sym => attributes[key]) }
   end
 end
 # rubocop:enable Style/BracesAroundHashParameters, Style/ClassAndModuleChildren
diff --git a/lib/super_diff/active_record/operation_tree_builders/active_record_model.rb b/lib/super_diff/active_record/operation_tree_builders/active_record_model.rb
index 72442b08..832462ea 100644
--- a/lib/super_diff/active_record/operation_tree_builders/active_record_model.rb
+++ b/lib/super_diff/active_record/operation_tree_builders/active_record_model.rb
@@ -9,8 +9,12 @@ def self.applies_to?(expected, actual)
 
         protected
 
+        def id
+          expected.class.primary_key
+        end
+
         def attribute_names
-          ["id"] + (expected.attributes.keys.sort - ["id"])
+          [id] + (expected.attributes.keys.sort - [id])
         end
       end
     end
diff --git a/spec/support/integration/matchers/produce_output_when_run_matcher.rb b/spec/support/integration/matchers/produce_output_when_run_matcher.rb
index 66859e40..43d3a9fd 100644
--- a/spec/support/integration/matchers/produce_output_when_run_matcher.rb
+++ b/spec/support/integration/matchers/produce_output_when_run_matcher.rb
@@ -12,7 +12,7 @@ def initialize(expected_output)
       end
 
       def removing_object_ids
-        first_replacing(/#<([\w:]+):0x[a-f0-9]+/, '#<\1')
+        first_replacing(/#<([\w_:]+):0x[a-f0-9]+/, '#<\1')
         self
       end
 
diff --git a/spec/support/models/active_record/person.rb b/spec/support/models/active_record/person.rb
index bf8ec2c5..c86a31e7 100644
--- a/spec/support/models/active_record/person.rb
+++ b/spec/support/models/active_record/person.rb
@@ -3,6 +3,7 @@ module Test
     module Models
       module ActiveRecord
         class Person < ::ActiveRecord::Base
+          self.primary_key = "person_id"
         end
       end
     end
@@ -13,7 +14,13 @@ class Person < ::ActiveRecord::Base
   config.before do
     ActiveRecord::Base
       .connection
-      .create_table(:people, force: true) do |t|
+      .create_table(
+        :people,
+        id: false,
+        primary_key: "person_id",
+        force: true
+      ) do |t|
+        t.primary_key :person_id, null: false
         t.string :name, null: false
         t.integer :age, null: false
       end
diff --git a/spec/support/shared_examples/active_record.rb b/spec/support/shared_examples/active_record.rb
index 076c0e88..4a172f4e 100644
--- a/spec/support/shared_examples/active_record.rb
+++ b/spec/support/shared_examples/active_record.rb
@@ -86,7 +86,7 @@
                 proc do
                   line do
                     plain "Expected "
-                    actual %|#<SuperDiff::Test::Models::ActiveRecord::Person id: nil, age: 31, name: "Elliot">|
+                    actual %|#<SuperDiff::Test::Models::ActiveRecord::Person person_id: nil, age: 31, name: "Elliot">|
                   end
 
                   line do
@@ -244,7 +244,7 @@
                 proc do
                   line do
                     plain "Expected "
-                    actual %|{ name: "Marty McFly", shipping_address: #<SuperDiff::Test::Models::ActiveRecord::Person id: nil, age: 31, name: "Elliot"> }|
+                    actual %|{ name: "Marty McFly", shipping_address: #<SuperDiff::Test::Models::ActiveRecord::Person person_id: nil, age: 31, name: "Elliot"> }|
                   end
 
                   line do
@@ -265,7 +265,7 @@
                   expected_line %|-     zip: "90382"|
                   expected_line "-   }>"
                   actual_line "+   shipping_address: #<SuperDiff::Test::Models::ActiveRecord::Person {"
-                  actual_line "+     id: nil,"
+                  actual_line "+     person_id: nil,"
                   actual_line "+     age: 31,"
                   actual_line %|+     name: "Elliot"|
                   actual_line "+   }>"
@@ -390,7 +390,7 @@
                 proc do
                   line do
                     plain "Expected "
-                    actual %|[#<SuperDiff::Test::Models::ActiveRecord::Query @results=#<ActiveRecord::Relation [#<SuperDiff::Test::Models::ActiveRecord::Person id: 1, age: 20, name: "Murphy">]>>]|
+                    actual %|[#<SuperDiff::Test::Models::ActiveRecord::Query @results=#<ActiveRecord::Relation [#<SuperDiff::Test::Models::ActiveRecord::Person person_id: 1, age: 20, name: "Murphy">]>>]|
                   end
 
                   line do
@@ -404,7 +404,7 @@
                   plain_line "    #<SuperDiff::Test::Models::ActiveRecord::Query {"
                   plain_line "      @results=#<ActiveRecord::Relation ["
                   plain_line "        #<SuperDiff::Test::Models::ActiveRecord::Person {"
-                  plain_line "          id: 1,"
+                  plain_line "          person_id: 1,"
                   # expected_line %|-         age: 19,|  # TODO
                   expected_line "-         age: 19"
                   actual_line "+         age: 20,"
diff --git a/spec/unit/active_record/object_inspection_spec.rb b/spec/unit/active_record/object_inspection_spec.rb
index fdd6a140..fe9f1c51 100644
--- a/spec/unit/active_record/object_inspection_spec.rb
+++ b/spec/unit/active_record/object_inspection_spec.rb
@@ -14,7 +14,7 @@
               as_lines: false
             )
           expect(string).to eq(
-            %(#<SuperDiff::Test::Models::ActiveRecord::Person id: nil, age: 31, name: "Elliot">)
+            %(#<SuperDiff::Test::Models::ActiveRecord::Person person_id: nil, age: 31, name: "Elliot">)
           )
         end
       end
@@ -91,7 +91,7 @@
             )
 
           expect(string).to eq(
-            %(#<ActiveRecord::Relation [#<SuperDiff::Test::Models::ActiveRecord::Person id: 1, age: 19, name: "Marty">, #<SuperDiff::Test::Models::ActiveRecord::Person id: 2, age: 17, name: "Jennifer">]>)
+            %(#<ActiveRecord::Relation [#<SuperDiff::Test::Models::ActiveRecord::Person person_id: 1, age: 19, name: "Marty">, #<SuperDiff::Test::Models::ActiveRecord::Person id: 2, age: 17, name: "Jennifer">]>)
           )
         end
       end