diff --git a/tools/iio/Makefile b/tools/iio/Makefile
index 332ed2f6c2c2..e22378dba244 100644
--- a/tools/iio/Makefile
+++ b/tools/iio/Makefile
@@ -12,7 +12,7 @@ endif
 # (this improves performance and avoids hard-to-debug behaviour);
 MAKEFLAGS += -r
 
-CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
+override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
 
 ALL_TARGETS := iio_event_monitor lsiio iio_generic_buffer
 ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))