diff --git a/toolkit/components/osfile/modules/osfile_async_front.jsm b/toolkit/components/osfile/modules/osfile_async_front.jsm
index 94c27c75f243..218cdbbf1454 100644
--- a/toolkit/components/osfile/modules/osfile_async_front.jsm
+++ b/toolkit/components/osfile/modules/osfile_async_front.jsm
@@ -1114,6 +1114,27 @@ File.remove = function remove(path, options) {
   return Scheduler.post("remove", [Type.path.toMsg(path), options], path);
 };
 
+// Extended attribute functions are MacOS only at this point.
+if (SharedAll.Constants.Sys.Name == "Darwin") {
+  /**
+   * Remove an extended attribute (xattr) from a file.
+   *
+   * @param {string} path The name of the file.
+   * @param {string} name The name of the extended attribute.
+   *
+   * @returns {promise}
+   * @resolves {null}
+   * @rejects {OS.File.Error} In case of an I/O error.
+   */
+  File.macRemoveXAttr = function macRemoveXAttr(path, name) {
+    return Scheduler.post(
+      "macRemoveXAttr",
+      [Type.path.toMsg(path), Type.cstring.toMsg(name)],
+      [path, name]
+    );
+  };
+}
+
 /**
  * Create a directory and, optionally, its parent directories.
  *
diff --git a/toolkit/components/osfile/modules/osfile_async_worker.js b/toolkit/components/osfile/modules/osfile_async_worker.js
index 034e94539d7a..b381bcb7d7e9 100644
--- a/toolkit/components/osfile/modules/osfile_async_worker.js
+++ b/toolkit/components/osfile/modules/osfile_async_worker.js
@@ -285,6 +285,12 @@ if (this.Components) {
     removeDir(path, options) {
       return File.removeDir(Type.path.fromMsg(path), options);
     },
+    macRemoveXAttr(path, name) {
+      return File.macRemoveXAttr(
+        Type.path.fromMsg(path),
+        Type.cstring.fromMsg(name)
+      );
+    },
     new_DirectoryIterator: function new_DirectoryIterator(path, options) {
       let directoryPath = Type.path.fromMsg(path);
       let iterator = new File.DirectoryIterator(directoryPath, options);
diff --git a/toolkit/components/osfile/modules/osfile_unix_back.jsm b/toolkit/components/osfile/modules/osfile_unix_back.jsm
index 4e45c3c6ecaa..5776ce2b690a 100644
--- a/toolkit/components/osfile/modules/osfile_unix_back.jsm
+++ b/toolkit/components/osfile/modules/osfile_unix_back.jsm
@@ -692,6 +692,20 @@
         ); // Other Unices
       }
 
+      if (OS.Constants.Sys.Name == "Darwin") {
+        // At the time of writing we only need this on MacOS.
+        libc.declareLazyFFI(
+          SysFile,
+          "removexattr",
+          "removexattr",
+          ctypes.default_abi,
+          /* return*/ Type.negativeone_or_nothing,
+          Type.path,
+          Type.cstring,
+          Type.int
+        );
+      }
+
       libc.declareLazyFFI(
         SysFile,
         "rename",
diff --git a/toolkit/components/osfile/modules/osfile_unix_front.jsm b/toolkit/components/osfile/modules/osfile_unix_front.jsm
index 76923b864bc9..2179c8eae08a 100644
--- a/toolkit/components/osfile/modules/osfile_unix_front.jsm
+++ b/toolkit/components/osfile/modules/osfile_unix_front.jsm
@@ -916,6 +916,24 @@
       return serialized;
     };
 
+    // Extended attribute functions are MacOS only at this point.
+    if (OS.Constants.Sys.Name == "Darwin") {
+      /**
+       * Remove an extended attribute (xattr) from a file.
+       *
+       * @param {string} path The name of the file.
+       * @param {string} name The name of the extended attribute.
+       *
+       * @throws {OS.File.Error} In case of an I/O error.
+       */
+      File.macRemoveXAttr = function removexattr(path, name) {
+        let result = UnixFile.removexattr(path, name, 0 /* follow links */);
+        if (result == -1) {
+          throw new File.Error("removexattr", ctypes.errno, path);
+        }
+      };
+    }
+
     let gStatData = new Type.stat.implementation();
     let gStatDataPtr = gStatData.address();