diff --git a/Assets/Tests/InputSystem/APIVerificationTests.cs b/Assets/Tests/InputSystem/APIVerificationTests.cs
index a32c881c44..32bfa184ea 100644
--- a/Assets/Tests/InputSystem/APIVerificationTests.cs
+++ b/Assets/Tests/InputSystem/APIVerificationTests.cs
@@ -250,6 +250,25 @@ public void API_MonoBehavioursHaveHelpUrls()
         Assert.That(monoBehaviourTypesHelpUrls, Has.All.StartWith(InputSystem.kDocUrl));
     }
 
+    [Test]
+    [Category("API")]
+    public void API_InputActionImporterHasHelpUrlToExistingManualPage()
+    {
+        const string manualPrefix = "/manual/";
+
+        var helpUrlAttribute = typeof(InputActionImporter).GetCustomAttribute<HelpURLAttribute>();
+        Assert.That(helpUrlAttribute, Is.Not.Null, "InputActionImporter has no HelpURL attribute, so the .inputactions Inspector help button falls back to a generated URL with no published page.");
+        Assert.That(helpUrlAttribute.URL, Does.StartWith(InputSystem.kDocUrl + manualPrefix));
+
+        var page = helpUrlAttribute.URL.Substring(InputSystem.kDocUrl.Length + manualPrefix.Length);
+        var anchorIndex = page.IndexOf('#');
+        if (anchorIndex >= 0)
+            page = page.Substring(0, anchorIndex);
+
+        var markdownPath = "Packages/com.unity.inputsystem/Documentation~/" + Path.ChangeExtension(page, ".md");
+        Assert.That(File.Exists(markdownPath), Is.True, $"HelpURL of InputActionImporter points at {helpUrlAttribute.URL} but {markdownPath} does not exist.");
+    }
+
     private const string kAPIDirectory = "Tools/API";
 
     ////FIXME: The .api-based checks are temporary and don't account for platform-specific APIs. Nuke these tests as soon
diff --git a/Packages/com.unity.inputsystem/CHANGELOG.md b/Packages/com.unity.inputsystem/CHANGELOG.md
index 5e13c71fe8..9a6d3514da 100644
--- a/Packages/com.unity.inputsystem/CHANGELOG.md
+++ b/Packages/com.unity.inputsystem/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Fixed
 
+- Fixed the Inspector help button for a selected `.inputactions` asset ("Open Reference for Input Action Importer") opening a missing documentation page; it now links to the Action Assets manual page [UUM-149518](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-149518)
 - Fixed an `OverflowException` when creating a control scheme (or other named item) whose all-numeric name exceeds `Int32.MaxValue`, which previously discarded the entered name and fell back to the default [UUM-145766](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-145766)
 - Fixed the Input Actions editor window logging a "Failed to load asset" exception on editor startup when its saved window layout was restored in a project where the referenced asset GUID did not resolve; the window now closes quietly instead [UUM-144318](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-144318)
 - Empty foldouts are no longer shown for processors and interactions that have no settings (e.g. "Invert") [UUM-144325](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-144325)
diff --git a/Packages/com.unity.inputsystem/InputSystem/Editor/AssetImporter/InputActionImporter.cs b/Packages/com.unity.inputsystem/InputSystem/Editor/AssetImporter/InputActionImporter.cs
index 126fb83de3..b572b29029 100644
--- a/Packages/com.unity.inputsystem/InputSystem/Editor/AssetImporter/InputActionImporter.cs
+++ b/Packages/com.unity.inputsystem/InputSystem/Editor/AssetImporter/InputActionImporter.cs
@@ -22,6 +22,7 @@ namespace UnityEngine.InputSystem.Editor
     /// Will not overwrite existing wrappers except if the generated code actually differs.
     /// </remarks>
     [ScriptedImporter(kVersion, InputActionAsset.Extension)]
+    [HelpURL(InputSystem.kDocUrl + "/manual/action-assets.html")]
     internal class InputActionImporter : ScriptedImporter
     {
         private const int kVersion = 14;