diff --git a/src/anytree/iterators/preorderiter.py b/src/anytree/iterators/preorderiter.py
index b07cf38..9e0d2e1 100644
--- a/src/anytree/iterators/preorderiter.py
+++ b/src/anytree/iterators/preorderiter.py
@@ -40,11 +40,18 @@ class PreOrderIter(AbstractIter):
 
     @staticmethod
     def _iter(children, filter_, stop, maxlevel):
-        for child_ in children:
+        cur_children = list(reversed(children))
+        descendantmaxlevel = maxlevel
+        while cur_children:
+            child_ = cur_children.pop()
             if stop(child_):
                 continue
             if filter_(child_):
                 yield child_
-            if not AbstractIter._abort_at_level(2, maxlevel):
-                descendantmaxlevel = maxlevel - 1 if maxlevel else None
+            if not AbstractIter._abort_at_level(2, descendantmaxlevel):
+                descendantmaxlevel = descendantmaxlevel - 1 if descendantmaxlevel else None
+                if len(child_.children) == 1:
+                    cur_children.append(child_.children[0])
+                    continue
                 yield from PreOrderIter._iter(child_.children, filter_, stop, descendantmaxlevel)
+            descendantmaxlevel = maxlevel
diff --git a/tests/test_iterators.py b/tests/test_iterators.py
index 78c8f1e..22fb0be 100644
--- a/tests/test_iterators.py
+++ b/tests/test_iterators.py
@@ -22,17 +22,23 @@ def test_preorder():
     g = Node("g", parent=f)
     i = Node("i", parent=g)
     h = Node("h", parent=i)
+    k = Node("k", parent=a)
+    o = Node("o", parent=k)
+    m = Node("m", parent=e)
 
-    eq_(list(PreOrderIter(f)), [f, b, a, d, c, e, g, i, h])
+    eq_(list(PreOrderIter(f)), [f, b, a, k, o, d, c, e, m, g, i, h])
     eq_(list(PreOrderIter(f, maxlevel=0)), [])
+    eq_(list(PreOrderIter(f, maxlevel=2)), [f, b, g])
     eq_(list(PreOrderIter(f, maxlevel=3)), [f, b, a, d, g, i])
-    eq_(list(PreOrderIter(f, filter_=lambda n: n.name not in ("e", "g"))), [f, b, a, d, c, i, h])
-    eq_(list(PreOrderIter(f, stop=lambda n: n.name == "d")), [f, b, a, g, i, h])
+    eq_(list(PreOrderIter(f, maxlevel=4)), [f, b, a, k, d, c, e, g, i, h])
+    eq_(list(PreOrderIter(f, maxlevel=f.height + 1)), list(PreOrderIter(f)))
+    eq_(list(PreOrderIter(f, filter_=lambda n: n.name not in ("e", "g"))), [f, b, a, k, o, d, c, m, i, h])
+    eq_(list(PreOrderIter(f, stop=lambda n: n.name == "d")), [f, b, a, k, o, g, i, h])
 
     it = PreOrderIter(f)
     eq_(next(it), f)
     eq_(next(it), b)
-    eq_(list(it), [a, d, c, e, g, i, h])
+    eq_(list(it), [a, k, o, d, c, e, m, g, i, h])
 
 
 def test_postorder():