diff -r 738de9a9a3ea Lib/warnings.py
--- a/Lib/warnings.py	Thu Aug 20 11:13:09 2015 +1200
+++ b/Lib/warnings.py	Sun Aug 23 09:56:35 2015 -0700
@@ -160,6 +160,20 @@
     return cat
 
 
+def _is_internal_frame(frame):
+    """Signal whether the frame is an internal CPython implementation detail."""
+    filename = frame.f_code.co_filename
+    return 'importlib' in filename and '_bootstrap' in filename
+
+
+def _next_external_frame(frame):
+    """Find the next frame that doesn't involve CPython internals."""
+    frame = frame.f_back
+    while frame is not None and _is_internal_frame(frame):
+        frame = frame.f_back
+    return frame
+
+
 # Code typically replaced by _warnings
 def warn(message, category=None, stacklevel=1):
     """Issue a warning, or maybe ignore it or raise an exception."""
@@ -174,13 +188,23 @@
                         "not '{:s}'".format(type(category).__name__))
     # Get context information
     try:
-        caller = sys._getframe(stacklevel)
+        if stacklevel <= 1 or _is_internal_frame(sys._getframe(1)):
+            # If frame is too small to care or if the warning originated in
+            # internal code, then do not try to hide any frames.
+            frame = sys._getframe(stacklevel)
+        else:
+            frame = sys._getframe(1)
+            # Look for one frame less since the above line starts us off.
+            for x in range(stacklevel-1):
+                frame = _next_external_frame(frame)
+                if frame is None:
+                    raise ValueError
     except ValueError:
         globals = sys.__dict__
         lineno = 1
     else:
-        globals = caller.f_globals
-        lineno = caller.f_lineno
+        globals = frame.f_globals
+        lineno = frame.f_lineno
     if '__name__' in globals:
         module = globals['__name__']
     else:
@@ -374,7 +398,6 @@
     defaultaction = _defaultaction
     onceregistry = _onceregistry
     _warnings_defaults = True
-
 except ImportError:
     filters = []
     defaultaction = "default"
diff -r 738de9a9a3ea Python/_warnings.c
--- a/Python/_warnings.c	Thu Aug 20 11:13:09 2015 +1200
+++ b/Python/_warnings.c	Sun Aug 23 09:56:35 2015 -0700
@@ -513,6 +513,58 @@
     return result;  /* Py_None or NULL. */
 }
 
+static int
+is_internal_frame(PyFrameObject *frame)
+{
+    PyObject *importlib_string = NULL;
+    PyObject *bootstrap_string = NULL;
+    PyObject *filename;
+    int contains;
+
+    if (importlib_string == NULL) {
+        importlib_string = PyUnicode_FromString("importlib");
+        if (importlib_string == NULL) {
+            return 0;  // XXX fatal error?
+        }
+
+        bootstrap_string = PyUnicode_FromString("_bootstrap");
+        if (bootstrap_string == NULL) {
+            return 0;  // XXX fatal error?
+        }
+        Py_INCREF(importlib_string);
+        Py_INCREF(bootstrap_string);
+    }
+
+    // XXX frame->f_code null?
+    filename = frame->f_code->co_filename;
+    // XXX possible to not be a string?
+    contains = PyUnicode_Contains(filename, importlib_string);
+    if (contains < 0) {
+        return 0;  // XXX fatal error?
+    }
+    else if (contains > 0) {
+        contains = PyUnicode_Contains(filename, bootstrap_string);
+        if (contains < 0) {
+            return 0;  // XXX fatal error?
+        }
+        else if (contains > 0) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
+static PyFrameObject *
+next_external_frame(PyFrameObject *frame)
+{
+    do {
+        frame = frame->f_back;
+    } while (frame != NULL && is_internal_frame(frame));
+
+    return frame;
+}
+
 /* filename, module, and registry are new refs, globals is borrowed */
 /* Returns 0 on error (no new refs), 1 on success */
 static int
@@ -523,8 +575,19 @@
 
     /* Setup globals and lineno. */
     PyFrameObject *f = PyThreadState_GET()->frame;
-    while (--stack_level > 0 && f != NULL)
-        f = f->f_back;
+    // Stack level comparisons to Python code is off by one as there is no
+    // warnings-related stack level to avoid.
+    // XXX
+    if (stack_level <= 0 || is_internal_frame(f)) {
+        while (--stack_level > 0 && f != NULL) {
+            f = f->f_back;
+        }
+    }
+    else {
+        while (--stack_level > 0 && f != NULL) {
+            f = next_external_frame(f);
+        }
+    }
 
     if (f == NULL) {
         globals = PyThreadState_Get()->interp->sysdict;