diff --git a/Modules/ThirdParty/ZLIB/src/CMakeLists.txt b/Modules/ThirdParty/ZLIB/src/CMakeLists.txt
index 084a55d2a0f..d4045cae453 100644
--- a/Modules/ThirdParty/ZLIB/src/CMakeLists.txt
+++ b/Modules/ThirdParty/ZLIB/src/CMakeLists.txt
@@ -2,7 +2,7 @@ set(INC_INSTALL_DIR "${ITKZLIB_INSTALL_INCLUDE_DIR}/itkzlib-ng")
 set(BIN_INSTALL_DIR "${ITKZLIB_INSTALL_RUNTIME_DIR}")
 set(LIB_INSTALL_DIR "${ITKZLIB_INSTALL_LIBRARY_DIR}")
 set(PKGCONFIG_INSTALL_DIR "${ITKZLIB_INSTALL_ARCHIVE_DIR}")
-set(ZLIB_SYMBOL_PREFIX "itkzlib_")
+set(ZLIB_SYMBOL_PREFIX "itkzlib_" CACHE INTERNAL "Hardcoded prefix for symbols in zlib")
 set(ZLIB_COMPAT ON)
 set(ZLIB_DUAL_LINK OFF)
 set(ZLIB_ENABLE_TESTS OFF)