diff --git a/pkg/tlsf/Makefile b/pkg/tlsf/Makefile
index fb27fb2749..f32e946dd4 100644
--- a/pkg/tlsf/Makefile
+++ b/pkg/tlsf/Makefile
@@ -2,6 +2,7 @@ PKG_NAME = tlsf
 PKG_VERSION = 3.0
 PKG_FILE = tlsf-$(PKG_VERSION).zip
 PKG_URL = http://download.riot-os.org/$(PKG_FILE)
+PKG_LICENSE = PD
 PKG_DIR=$(CURDIR)
 PKG_BUILDDIR=$(BINDIRBASE)/pkg/$(BOARD)/$(PKG_NAME)
 PKG_SRCDIR=$(PKG_BUILDDIR)/src