diff --git a/crates/ty/docs/configuration.md b/crates/ty/docs/configuration.md
index a2986eeb27..2b2f4a7282 100644
--- a/crates/ty/docs/configuration.md
+++ b/crates/ty/docs/configuration.md
@@ -76,6 +76,7 @@ python = "./.venv"
 Specifies the target platform that will be used to analyze the source code.
 If specified, ty will understand conditions based on comparisons with `sys.platform`, such
 as are commonly found in typeshed to reflect the differing contents of the standard library across platforms.
+If `all` is specified, ty will assume that the source code can run on any platform.
 
 If no platform is specified, ty will use the current platform:
 - `win32` for Windows
@@ -86,7 +87,7 @@ If no platform is specified, ty will use the current platform:
 
 **Default value**: `<current-platform>`
 
-**Type**: `"win32" | "darwin" | "android" | "ios" | "linux" | str`
+**Type**: `"win32" | "darwin" | "android" | "ios" | "linux" | "all" | str`
 
 **Example usage** (`pyproject.toml`):
 
diff --git a/crates/ty_project/src/metadata/options.rs b/crates/ty_project/src/metadata/options.rs
index 11dd846d58..44324209a1 100644
--- a/crates/ty_project/src/metadata/options.rs
+++ b/crates/ty_project/src/metadata/options.rs
@@ -333,6 +333,7 @@ pub struct EnvironmentOptions {
     /// Specifies the target platform that will be used to analyze the source code.
     /// If specified, ty will understand conditions based on comparisons with `sys.platform`, such
     /// as are commonly found in typeshed to reflect the differing contents of the standard library across platforms.
+    /// If `all` is specified, ty will assume that the source code can run on any platform.
     ///
     /// If no platform is specified, ty will use the current platform:
     /// - `win32` for Windows
@@ -343,7 +344,7 @@ pub struct EnvironmentOptions {
     #[serde(skip_serializing_if = "Option::is_none")]
     #[option(
         default = r#"<current-platform>"#,
-        value_type = r#""win32" | "darwin" | "android" | "ios" | "linux" | str"#,
+        value_type = r#""win32" | "darwin" | "android" | "ios" | "linux" | "all" | str"#,
         example = r#"
         # Tailor type stubs and conditionalized type definitions to windows.
         python-platform = "win32"
diff --git a/ty.schema.json b/ty.schema.json
index f4ae8d241b..2864a67963 100644
--- a/ty.schema.json
+++ b/ty.schema.json
@@ -88,7 +88,7 @@
           ]
         },
         "python-platform": {
-          "description": "Specifies the target platform that will be used to analyze the source code. If specified, ty will understand conditions based on comparisons with `sys.platform`, such as are commonly found in typeshed to reflect the differing contents of the standard library across platforms.\n\nIf no platform is specified, ty will use the current platform: - `win32` for Windows - `darwin` for macOS - `android` for Android - `ios` for iOS - `linux` for everything else",
+          "description": "Specifies the target platform that will be used to analyze the source code. If specified, ty will understand conditions based on comparisons with `sys.platform`, such as are commonly found in typeshed to reflect the differing contents of the standard library across platforms. If `all` is specified, ty will assume that the source code can run on any platform.\n\nIf no platform is specified, ty will use the current platform: - `win32` for Windows - `darwin` for macOS - `android` for Android - `ios` for iOS - `linux` for everything else",
           "anyOf": [
             {
               "$ref": "#/definitions/PythonPlatform"