diff --git a/ports/gsl/CMakeLists.txt b/ports/gsl/CMakeLists.txt
index 45abb5bd2..eb38a4431 100644
--- a/ports/gsl/CMakeLists.txt
+++ b/ports/gsl/CMakeLists.txt
@@ -48,6 +48,10 @@ file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/gsl_types.h "${GSLTYPES_H}")
 file(GLOB_RECURSE PUBLIC_HEADERS gsl*.h)
 list(APPEND PUBLIC_HEADERS ${CMAKE_CURRENT_BINARY_DIR}/gsl_types.h)
 
+# The debug libraries have a "d" postfix so that CMake's FindGSL.cmake 
+# module can distinguish between Release and Debug libraries
+set(CMAKE_DEBUG_POSTFIX "d")
+
 add_library(gslcblas ${CBLAS_SOURCES})
 set_target_properties(gslcblas PROPERTIES WINDOWS_EXPORT_ALL_SYMBOLS ON)
 
@@ -74,4 +78,4 @@ install(TARGETS gsl gslcblas
     LIBRARY DESTINATION lib
     ARCHIVE DESTINATION lib
     ${TARGET_INSTALL_OPTIONS}
-)
\ No newline at end of file
+)