diff --git a/db/sqlite3/src/Makefile.in b/db/sqlite3/src/Makefile.in
index b1cbce468932f..c1f0f853cbbda 100644
--- a/db/sqlite3/src/Makefile.in
+++ b/db/sqlite3/src/Makefile.in
@@ -77,6 +77,12 @@ export:: sqlite-version.h
 endif
 endif
 
+# XXX Force -O2 optimisation on Mac because using the default -O3 causes
+# crashes. See bug 676499.
+ifeq (cocoa,$(MOZ_WIDGET_TOOLKIT))
+MODULE_OPTIMIZE_FLAGS = -O2
+endif
+
 EXPORTS = \
   sqlite3.h \
   $(NULL)