diff --git a/icu4c/source/runConfigureICU b/icu4c/source/runConfigureICU
index 00055d4842a..7e2ab4a2158 100755
--- a/icu4c/source/runConfigureICU
+++ b/icu4c/source/runConfigureICU
@@ -218,8 +218,8 @@ case $platform in
         THE_COMP="Microsoft Visual C++"
         CC=cl; export CC
         CXX=cl; export CXX
-        RELEASE_CFLAGS='/O2 /Ob2'
-        RELEASE_CXXFLAGS='/O2 /Ob2'
+        RELEASE_CFLAGS='/O2 /Ob2 /Op'
+        RELEASE_CXXFLAGS='/O2 /Ob2 /Op'
         # The real debug flags are defined by the mh file because configure can't handle them.
         DEBUG_CFLAGS=
         DEBUG_CXXFLAGS=