diff --git a/js/src/builtin/Object.cpp b/js/src/builtin/Object.cpp
index e1e67539612f..8e2689d3e167 100644
--- a/js/src/builtin/Object.cpp
+++ b/js/src/builtin/Object.cpp
@@ -539,60 +539,6 @@ obj_getPrototypeOf(JSContext *cx, unsigned argc, Value *vp)
     return true;
 }
 
-static bool
-obj_setPrototypeOf(JSContext *cx, unsigned argc, Value *vp)
-{
-    CallArgs args = CallArgsFromVp(argc, vp);
-
-    RootedObject setPrototypeOf(cx, &args.callee());
-    if (!GlobalObject::warnOnceAboutPrototypeMutation(cx, setPrototypeOf))
-        return false;
-
-    if (args.length() < 2) {
-        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_MORE_ARGS_NEEDED,
-                             "Object.setPrototypeOf", "1", "");
-        return false;
-    }
-
-    /* Step 1-2. */
-    if (args[0].isNullOrUndefined()) {
-        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_CANT_CONVERT_TO,
-                             args[0].isNull() ? "null" : "undefined", "object");
-        return false;
-    }
-
-    /* Step 3. */
-    if (!args[1].isObjectOrNull()) {
-        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_NOT_EXPECTED_TYPE,
-                             "Object.setPrototypeOf", "an object or null", InformalValueTypeName(args[1]));
-        return false;
-    }
-
-    /* Step 4. */
-    if (!args[0].isObject()) {
-        args.rval().set(args[0]);
-        return true;
-    }
-
-    /* Step 5-6. */
-    RootedObject obj(cx, &args[0].toObject());
-    RootedObject newProto(cx, args[1].toObjectOrNull());
-
-    bool success;
-    if (!JSObject::setProto(cx, obj, newProto, &success))
-        return false;
-
-    /* Step 7. */
-    if (!success) {
-        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_OBJECT_NOT_EXTENSIBLE, "object");
-        return false;
-    }
-
-    /* Step 8. */
-    args.rval().set(args[0]);
-    return true;
-}
-
 #if JS_HAS_OBJ_WATCHPOINT
 
 bool
@@ -1068,7 +1014,6 @@ const JSFunctionSpec js::object_methods[] = {
 
 const JSFunctionSpec js::object_static_methods[] = {
     JS_FN("getPrototypeOf",            obj_getPrototypeOf,          1,0),
-    JS_FN("setPrototypeOf",            obj_setPrototypeOf,          2,0),
     JS_FN("getOwnPropertyDescriptor",  obj_getOwnPropertyDescriptor,2,0),
     JS_FN("keys",                      obj_keys,                    1,0),
     JS_FN("is",                        obj_is,                      2,0),
diff --git a/js/src/jit-test/tests/basic/setPrototypeOf.js b/js/src/jit-test/tests/basic/setPrototypeOf.js
deleted file mode 100644
index c5ac67148b3c..000000000000
--- a/js/src/jit-test/tests/basic/setPrototypeOf.js
+++ /dev/null
@@ -1,102 +0,0 @@
-load(libdir + 'asserts.js');
-
-function getObjects() {
-    function func(){}
-    return [func,
-            new func(),
-            {x: 5},
-            /regexp/,
-            [1, 2, 3],
-            new Date(),
-            new Number(1),
-            new Boolean(true),
-            new String('str'),
-            Object.create(null)];
-}
-
-var coercibleValues = [1,
-                       true,
-                       'string'];
-
-var nonCoercibleValues = [undefined,
-                          null];
-
-var valuesWithoutNull = coercibleValues.concat(undefined);
-
-function TestSetPrototypeOf(object, proto) {
-    assertEq(Object.setPrototypeOf(object, proto), object);
-    assertEq(Object.getPrototypeOf(object), proto);
-}
-
-// check if Object.setPrototypeOf works with coercible values
-for(var value of coercibleValues) {
-    assertEq(Object.setPrototypeOf(value, {}), value);
-
-    assertThrowsInstanceOf(() => Object.getPrototypeOf(value),
-        TypeError, "Coercible values should not have a prototype");
-}
-
-// check if Object.setPrototypeOf fails on non-coercible values
-for (var value of nonCoercibleValues) {
-    assertThrowsInstanceOf(() => Object.setPrototypeOf(value, {}),
-        TypeError, "Object.setPrototypeOf shouldn't work on non-coercible values");
-}
-
-// check if Object.setPrototypeOf works when prototype is set to non-objects
-var objects = getObjects();
-for (var object of objects) {
-    for (var proto of valuesWithoutNull) {
-        assertThrowsInstanceOf(() => Object.setPrototypeOf(object, proto),
-            TypeError, "Object.setPrototypeOf fails when the prototype is set to non-objects");
-    }
-}
-
-// check if Object.setPrototypeOf works when prototype is set to objects
-var objects1 = getObjects();
-var objects2 = getObjects();
-for (var object1 of objects1) {
-    for (var object2 of objects2) {
-        TestSetPrototypeOf(object1, object2);
-    }
-}
-
-// check if Object.setPrototypeOf works when prototype is set to null
-objects = getObjects();
-for (var object of objects) {
-    TestSetPrototypeOf(object, null);
-}
-
-// check if Object.setPrototypeOf fails when object is not extensible
-var objects = getObjects();
-var proto = {};
-for (var object of objects) {
-    Object.preventExtensions(object);
-    assertThrowsInstanceOf(() => Object.setPrototypeOf(object, proto),
-        TypeError, "Object.setPrototypeOf should fail when the object is not extensible");
-}
-
-// check if Object.setPrototypeOf works with prototype lookup
-var object = {};
-assertEq('x' in object, false);
-assertEq('y' in object, false);
-
-var oldProto = {
-    x: 'old x',
-    y: 'old y'
-};
-Object.setPrototypeOf(object, oldProto);
-assertEq(object.x, 'old x');
-assertEq(object.y, 'old y');
-
-var newProto = {
-    x: 'new x'
-};
-Object.setPrototypeOf(object, newProto);
-assertEq(object.x, 'new x');
-assertEq('y' in object, false);
-
-// check if Object.setPrototypeOf throws TypeError on fewer arguments
-assertThrowsInstanceOf(() => Object.setPrototypeOf(),
-    TypeError, "Object.setPrototypeOf throws TypeError when called without any parameters");
-assertThrowsInstanceOf(() => Object.setPrototypeOf({}),
-    TypeError, "Object.setPrototypeOf throws TypeError when called with 1 parameter");