diff --git a/lib/licenses.nix b/lib/licenses.nix
index 9546f83844c..fd9b4eaeb31 100644
--- a/lib/licenses.nix
+++ b/lib/licenses.nix
@@ -285,6 +285,12 @@ rec {
 
   unfreeRedistributableFirmware = "unfree-redistributable-firmware";
 
+  unlicense = {
+    shortName = "Unlicense";
+    fullName = "Unlicense";
+    url = http://unlicense.org/;
+  };
+
   wadalab = {
     shortName = "wadalab";
     fullName = "Wadalab Font License";
diff --git a/pkgs/tools/misc/youtube-dl/default.nix b/pkgs/tools/misc/youtube-dl/default.nix
index bf23fbcf2cf..bff266a25e7 100644
--- a/pkgs/tools/misc/youtube-dl/default.nix
+++ b/pkgs/tools/misc/youtube-dl/default.nix
@@ -26,6 +26,7 @@ stdenv.mkDerivation rec {
     homepage = "http://rg3.github.com/youtube-dl/";
     repositories.git = https://github.com/rg3/youtube-dl.git;
     description = "Command-line tool to download videos from YouTube.com and other sites";
+    license = stdenv.lib.licenses.unlicense;
 
     platforms = with stdenv.lib.platforms; linux ++ darwin;
     maintainers = with stdenv.lib.maintainers; [ bluescreen303 simons phreedom ];