diff --git a/pkgs/development/libraries/tl-expected/default.nix b/pkgs/development/libraries/tl-expected/default.nix
new file mode 100644
index 00000000000..9de97229e0b
--- /dev/null
+++ b/pkgs/development/libraries/tl-expected/default.nix
@@ -0,0 +1,24 @@
+{ stdenv, fetchFromGitHub, cmake }:
+
+stdenv.mkDerivation rec {
+  pname = "tl-expected-unstable";
+  version = "2019-11-11"; # 5 commits ahead of version 1.0.0
+
+  src = fetchFromGitHub {
+    owner = "TartanLlama";
+    repo = "expected";
+    rev = "1d9c5d8c0da84b8ddc54bd3d90d632eec95c1f13";
+    fetchSubmodules = true;
+    sha256 = "0rzfn9yyg70zwpxbmv22qy0015baymi2rdd65ixmcb31fgnap68i";
+  };
+
+  nativeBuildInputs = [ cmake ];
+
+  meta = with stdenv.lib; {
+    description = "C++11/14/17 std::expected with functional-style extensions";
+    homepage = https://tl.tartanllama.xyz/en/latest/api/expected.html;
+    license = licenses.cc0;
+    platforms = platforms.all;
+    maintainers = with maintainers; [ primeos ];
+  };
+}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index cb4016b4971..e645277627c 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -14458,6 +14458,8 @@ in
   tk-8_6 = callPackage ../development/libraries/tk/8.6.nix { };
   tk-8_5 = callPackage ../development/libraries/tk/8.5.nix { tcl = tcl-8_5; };
 
+  tl-expected = callPackage ../development/libraries/tl-expected { };
+
   tnt = callPackage ../development/libraries/tnt { };
 
   tntnet = callPackage ../development/libraries/tntnet { };