diff --git a/core/tests/regression_tests.rs b/core/tests/regression_tests.rs
index 82242556c..60c4d4b64 100644
--- a/core/tests/regression_tests.rs
+++ b/core/tests/regression_tests.rs
@@ -135,6 +135,7 @@ swf_tests! {
     (movieclip_prototype_extension, "avm1/movieclip_prototype_extension", 1),
     (movieclip_hittest, "avm1/movieclip_hittest", 1),
     (movieclip_hittest_shapeflag, "avm1/movieclip_hittest_shapeflag", 10),
+    #[ignore] (movieclip_lockroot, "avm1/movieclip_lockroot", 10),
     #[ignore] (textfield_text, "avm1/textfield_text", 1),
     (recursive_prototypes, "avm1/recursive_prototypes", 2),
     (stage_object_children, "avm1/stage_object_children", 2),
diff --git a/core/tests/swfs/avm1/movieclip_lockroot/child.as b/core/tests/swfs/avm1/movieclip_lockroot/child.as
new file mode 100644
index 000000000..7ef68a743
--- /dev/null
+++ b/core/tests/swfs/avm1/movieclip_lockroot/child.as
@@ -0,0 +1,7 @@
+function setLock(lock) {
+	this._lockroot = lock;
+}
+
+function test(lock) {
+	trace("Child: level is " + this + ", root is " + _root + ", _lockroot is " + this._lockroot + ", parent is " + this._parent);
+}
diff --git a/core/tests/swfs/avm1/movieclip_lockroot/child.fla b/core/tests/swfs/avm1/movieclip_lockroot/child.fla
new file mode 100644
index 000000000..78dca7b18
Binary files /dev/null and b/core/tests/swfs/avm1/movieclip_lockroot/child.fla differ
diff --git a/core/tests/swfs/avm1/movieclip_lockroot/child.swf b/core/tests/swfs/avm1/movieclip_lockroot/child.swf
new file mode 100644
index 000000000..530631f17
Binary files /dev/null and b/core/tests/swfs/avm1/movieclip_lockroot/child.swf differ
diff --git a/core/tests/swfs/avm1/movieclip_lockroot/output.txt b/core/tests/swfs/avm1/movieclip_lockroot/output.txt
new file mode 100644
index 000000000..48d39bc24
--- /dev/null
+++ b/core/tests/swfs/avm1/movieclip_lockroot/output.txt
@@ -0,0 +1,29 @@
+Parent: level is _level0, root is _level0, _lockroot is false
+Parent: setting _lockroot to true sets it to true.
+Parent: setting _lockroot to false sets it to false.
+Parent: setting _lockroot to undefined sets it to false.
+Parent: setting _lockroot to null sets it to false.
+Parent: setting _lockroot to NaN sets it to false.
+Parent: setting _lockroot to -1 sets it to true.
+Parent: setting _lockroot to 0 sets it to false.
+Parent: setting _lockroot to 1 sets it to true.
+Parent: setting _lockroot to 1337 sets it to true.
+Parent: setting _lockroot to "true" sets it to true.
+Parent: setting _lockroot to "false" sets it to true.
+Parent: setting _lockroot to "foo" sets it to true.
+Parent: setting _lockroot to "" sets it to false.
+Parent: setting _lockroot to "0" sets it to true.
+Parent: setting _lockroot to [object Object] sets it to true.
+Child: level is _level0.child1, root is _level0, _lockroot is false, parent is _level0
+Child: level is _level0.child2, root is _level0.child2, _lockroot is true, parent is _level0
+Child: level is _level0.child3, root is _level0.child3, _lockroot is true, parent is _level0
+Child: level is _level0.child1.child1, root is _level0, _lockroot is false, parent is _level0.child1
+Child: level is _level0.child1.child2, root is _level0.child1.child2, _lockroot is true, parent is _level0.child1
+Child: level is _level0.child1.child3, root is _level0.child1.child3, _lockroot is true, parent is _level0.child1
+Child: level is _level0.child2.child1, root is _level0.child2, _lockroot is false, parent is _level0.child2
+Child: level is _level0.child2.child2, root is _level0.child2.child2, _lockroot is true, parent is _level0.child2
+Child: level is _level0.child2.child3, root is _level0.child2.child3, _lockroot is true, parent is _level0.child2
+Child: level is _level0.child3.child1, root is _level0.child3, _lockroot is false, parent is _level0.child3
+Child: level is _level0.child3.child2, root is _level0.child3.child2, _lockroot is true, parent is _level0.child3
+Child: level is _level0.child3.child3, root is _level0.child3.child3, _lockroot is true, parent is _level0.child3
+All tests done.
diff --git a/core/tests/swfs/avm1/movieclip_lockroot/test.as b/core/tests/swfs/avm1/movieclip_lockroot/test.as
new file mode 100644
index 000000000..6fc07b15a
--- /dev/null
+++ b/core/tests/swfs/avm1/movieclip_lockroot/test.as
@@ -0,0 +1,122 @@
+var levels = 1;
+
+function testSet(value) {
+	var valueLabel = typeof value == "string" ? "\"" + value + "\"" : value;
+	this._lockroot = false;
+	this._lockroot = value;
+	if (this._lockroot) {
+		trace("Parent: setting _lockroot to " + valueLabel + " sets it to true.");
+		this._lockroot = false;
+		return;
+	}
+	this._lockroot = true;
+	this._lockroot = value;
+	if (!this._lockroot) {
+		trace("Parent: setting _lockroot to " + valueLabel + " sets it to false.");
+		return;
+	}
+	
+	this._lockroot = false;
+	trace("Parent: setting _lockroot to " + valueLabel + " has no effect.");
+}
+
+function testSelf() {
+	// Prints _level0, _level0, false
+	trace("Parent: level is " + this + ", root is " + _root + ", _lockroot is " + this._lockroot);
+	
+	// Edge case tests
+	testSet(true); /// true
+	testSet(false); // false
+	testSet(undefined); //false
+	testSet(null); // false
+	testSet(NaN); // false
+	testSet(-1); // true
+	testSet(0); // false
+	testSet(1); // true
+	testSet(1337); // true
+	testSet("true"); // true
+	testSet("false"); // true
+	testSet("foo"); // true
+	testSet(""); // false
+	testSet("0"); // true
+	testSet({}); // true
+}
+
+function testChildren() {
+	// 1 = normal child, lockroot unset
+	// 2 = lockroot set on container before loading (must inherit)
+	// 3 = lockroot set by child function
+	
+	// Top
+	createEmptyMovieClip("child1", levels++);
+	child1.loadMovie("child.swf");
+	createEmptyMovieClip("child2", levels++);
+	child2._lockroot = true;
+	child2.loadMovie("child.swf");
+	createEmptyMovieClip("child3", levels++);
+	child3.loadMovie("child.swf");
+	
+	// Wait for initial loads
+	setTimeout(createGrandChildren, 50);
+	
+	// Test it all
+	setTimeout(testAllChildren, 250);
+}
+
+function createGrandChildren() {
+	// Each grandchild
+	_root.child1.createEmptyMovieClip("child1", levels++);
+	_root.child1.child1.loadMovie("child.swf");
+	_root.child1.createEmptyMovieClip("child2", levels++);
+	_root.child1.child2._lockroot = true;
+	_root.child1.child2.loadMovie("child.swf");
+	_root.child1.createEmptyMovieClip("child3", levels++);
+	_root.child1.child3.loadMovie("child.swf");
+
+	_root.child2.createEmptyMovieClip("child1", levels++);
+	_root.child2.child1.loadMovie("child.swf");
+	_root.child2.createEmptyMovieClip("child2", levels++);
+	_root.child2.child2._lockroot = true;
+	_root.child2.child2.loadMovie("child.swf");
+	_root.child2.createEmptyMovieClip("child3", levels++);
+	_root.child2.child3.loadMovie("child.swf");
+
+	_root.child3.createEmptyMovieClip("child1", levels++);
+	_root.child3.child1.loadMovie("child.swf");
+	_root.child3.createEmptyMovieClip("child2", levels++);
+	_root.child3.child2._lockroot = true;
+	_root.child3.child2.loadMovie("child.swf");
+	_root.child3.createEmptyMovieClip("child3", levels++);
+	_root.child3.child3.loadMovie("child.swf");
+}
+
+function testAllChildren() {
+	_root.child1.test(); // Root is _level0, lockroot false
+	_root.child2.test(); // Root is self, lockroot true
+	_root.child3.setLock(true);
+	_root.child3.test(); // Root is self, lockroot true
+
+	_root.child1.child1.test(); // Root is _level0, lockroot false
+	_root.child1.child2.test(); // Root is self, lockroot true
+	_root.child1.child3.setLock(true);
+	_root.child1.child3.test(); // Root is self, lockroot true
+
+	_root.child2.child1.test(); // Root is _parent, lockroot true
+	_root.child2.child2.test(); // Root is self, lockroot true
+	_root.child2.child3.setLock(true);
+	_root.child2.child3.test(); // Root is self, lockroot true
+
+	_root.child3.child1.test(); // Root is _parent, lockroot true
+	_root.child3.child2.test(); // Root is self, lockroot true
+	_root.child3.child3.setLock(true);
+	_root.child3.child3.test(); // Root is self, lockroot true
+	
+	trace("All tests done.");
+}
+
+function test() {
+	testSelf();
+	testChildren();
+}
+
+test();
\ No newline at end of file
diff --git a/core/tests/swfs/avm1/movieclip_lockroot/test.fla b/core/tests/swfs/avm1/movieclip_lockroot/test.fla
new file mode 100644
index 000000000..2e0857d35
Binary files /dev/null and b/core/tests/swfs/avm1/movieclip_lockroot/test.fla differ
diff --git a/core/tests/swfs/avm1/movieclip_lockroot/test.swf b/core/tests/swfs/avm1/movieclip_lockroot/test.swf
new file mode 100644
index 000000000..166825627
Binary files /dev/null and b/core/tests/swfs/avm1/movieclip_lockroot/test.swf differ