diff --git a/ports/openssl/unix/CMakeLists.txt b/ports/openssl/unix/CMakeLists.txt
index 6184d6494a6433..977017f8d55322 100644
--- a/ports/openssl/unix/CMakeLists.txt
+++ b/ports/openssl/unix/CMakeLists.txt
@@ -46,10 +46,12 @@ message("CMAKE_C_COMPILER=${CMAKE_C_COMPILER}")
 message("COMPILER_ROOT=${COMPILER_ROOT}")
 message("CMAKE_SYSROOT=${CMAKE_SYSROOT}")
 message("CMAKE_OSX_SYSROOT=${CMAKE_OSX_SYSROOT}")
+message("CMAKE_OSX_DEPLOYMENT_TARGET=${CMAKE_OSX_DEPLOYMENT_TARGET}")
 message("CMAKE_C_FLAGS=${CMAKE_C_FLAGS}")
 message("CMAKE_C_FLAGS_RELEASE=${CMAKE_C_FLAGS_RELEASE}")
 message("CMAKE_C_FLAGS_DEBUG=${CMAKE_C_FLAGS_DEBUG}")
 message("CMAKE_INCLUDE_SYSTEM_FLAG_C=${CMAKE_INCLUDE_SYSTEM_FLAG_C}")
+message("CMAKE_C_OSX_DEPLOYMENT_TARGET_FLAG=${CMAKE_C_OSX_DEPLOYMENT_TARGET_FLAG}")
 
 set(CFLAGS "${CMAKE_C_FLAGS}")
 if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
@@ -66,6 +68,9 @@ if(CMAKE_SYSROOT AND CMAKE_C_COMPILE_OPTIONS_SYSROOT)
 elseif(CMAKE_OSX_SYSROOT AND CMAKE_C_COMPILE_OPTIONS_SYSROOT)
     set(CFLAGS "${CFLAGS} ${CMAKE_C_COMPILE_OPTIONS_SYSROOT}${CMAKE_OSX_SYSROOT}")
 endif()
+if (CMAKE_OSX_DEPLOYMENT_TARGET AND CMAKE_C_OSX_DEPLOYMENT_TARGET_FLAG)
+    set(CFLAGS "${CFLAGS} ${CMAKE_C_OSX_DEPLOYMENT_TARGET_FLAG}${CMAKE_OSX_DEPLOYMENT_TARGET}")
+endif()
 
 string(REGEX REPLACE "^ " "" CFLAGS "${CFLAGS}")