diff --git a/lib/mix/tasks/docs.ex b/lib/mix/tasks/docs.ex
index 29992a3f6..f89971224 100644
--- a/lib/mix/tasks/docs.ex
+++ b/lib/mix/tasks/docs.ex
@@ -114,6 +114,9 @@ defmodule Mix.Tasks.Docs do
 
     * `:output` - Output directory for the generated docs; default: "doc".
       May be overridden by command line argument.
+    
+    *`:ignore_apps` - Apps to be ignored when generating documentation in an umbrella project.
+      Receives a list of atoms. Example: `[:first_app, :second_app]`.
 
   ## Groups
 
@@ -158,7 +161,8 @@ defmodule Mix.Tasks.Docs do
   ## Umbrella project
 
   ExDoc can be used in an umbrella project and generates a single documentation
-  for all child apps.
+  for all child apps. You can use the `:ignore_apps` configuration to exclude
+  certain projects in the umbrella from documentation.
 
   Generating documentation per each child app can be achieved by running:
 
@@ -249,7 +253,7 @@ defmodule Mix.Tasks.Docs do
   defp normalize_source_beam(options, config) do
     compile_path =
       if Mix.Project.umbrella?(config) do
-        umbrella_compile_paths()
+        umbrella_compile_paths(Keyword.get(options, :ignore_apps, []))
       else
         Mix.Project.compile_path()
       end
@@ -257,10 +261,11 @@ defmodule Mix.Tasks.Docs do
     Keyword.put_new(options, :source_beam, compile_path)
   end
 
-  defp umbrella_compile_paths do
+  defp umbrella_compile_paths(ignored_apps) do
     build = Mix.Project.build_path()
 
-    for {app, _} <- Mix.Project.apps_paths() do
+    for {app, _} <- Mix.Project.apps_paths(),
+        app not in ignored_apps do
       Path.join([build, "lib", Atom.to_string(app), "ebin"])
     end
   end
diff --git a/test/mix/tasks/docs_test.exs b/test/mix/tasks/docs_test.exs
index c2b084e1f..da99ad857 100644
--- a/test/mix/tasks/docs_test.exs
+++ b/test/mix/tasks/docs_test.exs
@@ -11,80 +11,117 @@ defmodule Mix.Tasks.DocsTest do
 
   test "inflects values from app and version" do
     assert [{"ex_doc", "0.1.0", [formatter: "html", deps: _, source_beam: _]}] =
-           run([], [app: :ex_doc, version: "0.1.0"])
+             run([], app: :ex_doc, version: "0.1.0")
   end
 
   test "accepts multiple formatters from CLI" do
-    assert [{"ex_doc", "0.1.0", [formatter: "html", deps: _, source_beam: _]},
-            {"ex_doc", "0.1.0", [formatter: "epub", deps: _, source_beam: _]}] =
-           run(["-f", "html", "-f", "epub"], [app: :ex_doc, version: "0.1.0"])
+    assert [
+             {"ex_doc", "0.1.0", [formatter: "html", deps: _, source_beam: _]},
+             {"ex_doc", "0.1.0", [formatter: "epub", deps: _, source_beam: _]}
+           ] = run(["-f", "html", "-f", "epub"], app: :ex_doc, version: "0.1.0")
   end
 
   test "accepts multiple formatters from config" do
-    assert [{"ex_doc", "0.1.0", [formatter: "html", deps: _, source_beam: _, formatters: _]},
-            {"ex_doc", "0.1.0", [formatter: "epub", deps: _, source_beam: _, formatters: _]}] =
-           run([], [app: :ex_doc, version: "0.1.0", docs: [formatters: ["html", "epub"]]])
+    assert [
+             {"ex_doc", "0.1.0", [formatter: "html", deps: _, source_beam: _, formatters: _]},
+             {"ex_doc", "0.1.0", [formatter: "epub", deps: _, source_beam: _, formatters: _]}
+           ] = run([], app: :ex_doc, version: "0.1.0", docs: [formatters: ["html", "epub"]])
   end
 
   test "uses the given name" do
     assert [{"ExDoc", "0.1.0", [formatter: "html", deps: _, source_beam: _]}] =
-           run([], [app: :ex_doc, version: "0.1.0", name: "ExDoc"])
+             run([], app: :ex_doc, version: "0.1.0", name: "ExDoc")
   end
 
   test "accepts modules in :main" do
-    assert [{"ex_doc", "dev", [formatter: "html", deps: _, main: "Sample", source_beam: _, ]}] =
-           run([], [app: :ex_doc, docs: [main: Sample]])
+    assert [{"ex_doc", "dev", [formatter: "html", deps: _, main: "Sample", source_beam: _]}] =
+             run([], app: :ex_doc, docs: [main: Sample])
   end
 
   test "accepts files in :main" do
     assert [{"ex_doc", "dev", [formatter: "html", deps: _, source_beam: _, main: "another"]}] =
-           run([], [app: :ex_doc, docs: [main: "another"]])
+             run([], app: :ex_doc, docs: [main: "another"])
   end
 
   test "accepts output in :output" do
     assert [{"ex_doc", "dev", [formatter: "html", deps: _, source_beam: _, output: "hello"]}] =
-           run([], [app: :ex_doc, docs: [output: "hello"]])
+             run([], app: :ex_doc, docs: [output: "hello"])
   end
 
   test "parses output with lower preference than options" do
     assert [{"ex_doc", "dev", [formatter: "html", deps: _, source_beam: _, output: "world"]}] =
-           run(~w(-o world), [app: :ex_doc, docs: [output: "world"]])
+             run(~w(-o world), app: :ex_doc, docs: [output: "world"])
   end
 
   test "includes dependencies" do
     assert [{"ex_doc", "dev", [formatter: "html", deps: deps, source_beam: _]}] =
-           run([], [app: :ex_doc, docs: []])
+             run([], app: :ex_doc, docs: [])
+
     assert List.keyfind(deps, Application.app_dir(:earmark), 0) ==
-           {Application.app_dir(:earmark), "https://hexdocs.pm/earmark/#{Application.spec(:earmark, :vsn)}/"}
+             {Application.app_dir(:earmark),
+              "https://hexdocs.pm/earmark/#{Application.spec(:earmark, :vsn)}/"}
   end
 
   test "allows custom dependency paths" do
     assert [{"ex_doc", "dev", [formatter: "html", deps: deps, source_beam: _]}] =
-           run([], [app: :ex_doc, docs: [deps: [earmark: "foo"]]])
+             run([], app: :ex_doc, docs: [deps: [earmark: "foo"]])
+
     assert List.keyfind(deps, Application.app_dir(:earmark), 0) ==
-           {Application.app_dir(:earmark), "foo"}
+             {Application.app_dir(:earmark), "foo"}
   end
 
   test "accepts lazy docs" do
     assert [{"ex_doc", "dev", [formatter: "html", deps: _, source_beam: _, main: "another"]}] =
-           run([], [app: :ex_doc, docs: fn -> [main: "another"] end])
+             run([], app: :ex_doc, docs: fn -> [main: "another"] end)
   end
 
   test "accepts options from root" do
     # accepted options are: `app`, `name`, `source_url`, `homepage_url`, `version`
-    assert [{"ExDoc", "1.2.3-dev",
-             [formatter: "html",
-              deps: _, source_beam: _,
-              homepage_url: "http://elixir-lang.org",
-              source_url: "https://github.com/elixir-lang/ex_doc",
-              ]}] =
-           run([], [app: :ex_doc,
-                    name: "ExDoc",
-                    source_url: "https://github.com/elixir-lang/ex_doc",
-                    homepage_url: "http://elixir-lang.org",
-                    version: "1.2.3-dev",
-                   ])
-
-    assert [{"ex_doc", "dev", _}] = run([], [app: :ex_doc])
+    assert [
+             {"ExDoc", "1.2.3-dev",
+              [
+                formatter: "html",
+                deps: _,
+                source_beam: _,
+                homepage_url: "http://elixir-lang.org",
+                source_url: "https://github.com/elixir-lang/ex_doc"
+              ]}
+           ] =
+             run([],
+               app: :ex_doc,
+               name: "ExDoc",
+               source_url: "https://github.com/elixir-lang/ex_doc",
+               homepage_url: "http://elixir-lang.org",
+               version: "1.2.3-dev"
+             )
+
+    assert [{"ex_doc", "dev", _}] = run([], app: :ex_doc)
+  end
+
+  test "supports umbrella project" do
+    Mix.Project.in_project(:umbrella, "test/fixtures/umbrella", fn _mod ->
+      [
+        {"umbrella", "dev",
+         [
+           formatter: "html",
+           deps: _,
+           source_beam: _
+         ]}
+      ] = run([], app: :umbrella, apps_path: "apps/", docs: [])
+    end)
+  end
+
+  test "supports umbrella project with ignore_apps" do
+    Mix.Project.in_project(:umbrella, "test/fixtures/umbrella", fn _mod ->
+      [
+        {"umbrella", "dev",
+         [
+           formatter: "html",
+           deps: _,
+           source_beam: _,
+           ignore_apps: [:foo]
+         ]}
+      ] = run([], app: :umbrella, apps_path: "apps/", docs: [ignore_apps: [:foo]])
+    end)
   end
 end