diff --git a/src/posix/Makefile.am b/src/posix/Makefile.am
index fbe181455..dff3d76d5 100644
--- a/src/posix/Makefile.am
+++ b/src/posix/Makefile.am
@@ -51,6 +51,7 @@ CPPFLAGS_COMMON                                                        = \
     -I$(top_srcdir)/src/core                                             \
     -I$(top_srcdir)/src/posix/platform                                   \
     -D_GNU_SOURCE                                                        \
+    $(OPENTHREAD_TARGET_DEFINES)                                         \
     $(NULL)
 
 LIBTOOLFLAGS_COMMON = --preserve-dup-deps
diff --git a/src/posix/platform/Makefile.am b/src/posix/platform/Makefile.am
index edb6a107c..22deb4792 100644
--- a/src/posix/platform/Makefile.am
+++ b/src/posix/platform/Makefile.am
@@ -36,6 +36,7 @@ libopenthread_posix_a_CPPFLAGS            = \
     -I$(top_srcdir)/src/ncp                 \
     -I$(top_srcdir)/src/posix/platform      \
     -D_GNU_SOURCE                           \
+    $(OPENTHREAD_TARGET_DEFINES)            \
     $(NULL)
 
 libopenthread_posix_a_SOURCES             = \