diff --git a/res/composer-schema.json b/res/composer-schema.json
index 9df390e06..efe7a5e59 100644
--- a/res/composer-schema.json
+++ b/res/composer-schema.json
@@ -323,6 +323,26 @@
                     "example": "my-extension-source",
                     "default": null
                 },
+                "os-families": {
+                    "type": "array",
+                    "minItems": 1,
+                    "description": "An array of OS families to mark as compatible with the extension. Specifying this property will mean this package is not installable with PIE on any OS family not listed here. Must not be specified alongside os-families-exclude.",
+                    "items": {
+                        "type": "string",
+                        "enum": ["windows", "bsd", "darwin", "solaris", "linux", "unknown"],
+                        "description": "The name of the OS family to mark as compatible."
+                    }
+                },
+                "os-families-exclude": {
+                    "type": "array",
+                    "minItems": 1,
+                    "description": "An array of OS families to mark as incompatible with the extension. Specifying this property will mean this package is installable on any OS family except those listed here. Must not be specified alongside os-families.",
+                    "items": {
+                        "type": "string",
+                        "enum": ["windows", "bsd", "darwin", "solaris", "linux", "unknown"],
+                        "description": "The name of the OS family to exclude."
+                    }
+                },
                 "configure-options": {
                     "type": "array",
                     "description": "These configure options make up the flags that can be passed to ./configure when installing the extension.",
@@ -350,7 +370,14 @@
                         }
                     }
                 }
-            }
+            },
+            "allOf": [
+                {
+                    "not": {
+                        "required": ["os-families", "os-families-exclude"]
+                    }
+                }
+            ]
         },
         "config": {
             "type": "object",
diff --git a/src/Composer/Package/PackageInterface.php b/src/Composer/Package/PackageInterface.php
index dec040334..d3849781a 100644
--- a/src/Composer/Package/PackageInterface.php
+++ b/src/Composer/Package/PackageInterface.php
@@ -23,7 +23,7 @@ use Composer\Repository\RepositoryInterface;
  *
  * @phpstan-type AutoloadRules    array{psr-0?: array<string, string|string[]>, psr-4?: array<string, string|string[]>, classmap?: list<string>, files?: list<string>, exclude-from-classmap?: list<string>}
  * @phpstan-type DevAutoloadRules array{psr-0?: array<string, string|string[]>, psr-4?: array<string, string|string[]>, classmap?: list<string>, files?: list<string>}
- * @phpstan-type PhpExtConfig     array{extension-name?: string, priority?: int, support-zts?: bool, support-nts?: bool, build-path?: string|null, configure-options?: list<array{name: string, description?: string}>}
+ * @phpstan-type PhpExtConfig     array{extension-name?: string, priority?: int, support-zts?: bool, support-nts?: bool, build-path?: string|null, os-families?: non-empty-list<non-empty-string>, os-families-exclude?: non-empty-list<non-empty-string>, configure-options?: list<array{name: string, description?: string}>}
  */
 interface PackageInterface
 {