diff --git a/Lib/idlelib/GrepDialog.py b/Lib/idlelib/GrepDialog.py
index 01e0483d4b27..27fcc33c329e 100644
--- a/Lib/idlelib/GrepDialog.py
+++ b/Lib/idlelib/GrepDialog.py
@@ -81,7 +81,7 @@ def grep_it(self, prog, path):
         hits = 0
         for fn in list:
             try:
-                f = open(fn)
+                f = open(fn, errors='replace')
             except IOError as msg:
                 print(msg)
                 continue
diff --git a/Misc/NEWS b/Misc/NEWS
index 3e4157ecfded..bd296cac7256 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -49,6 +49,9 @@ Core and Builtins
 Library
 -------
 
+- Issue14929: Stop Idle 3.x from closing on Unicode decode errors when grepping.
+  Patch by Roger Serwy.
+
 - Issue #12515: email now registers a defect if it gets to EOF while parsing
   a MIME part without seeing the closing MIME boundary.