diff --git a/pkgs/development/libraries/ada/gnatcoll/core.nix b/pkgs/development/libraries/ada/gnatcoll/core.nix
new file mode 100644
index 000000000000..f5f84342137e
--- /dev/null
+++ b/pkgs/development/libraries/ada/gnatcoll/core.nix
@@ -0,0 +1,47 @@
+{ stdenv
+, lib
+, gnat
+, gprbuild
+, fetchFromGitHub
+, xmlada
+, which
+}:
+
+stdenv.mkDerivation rec {
+  pname = "gnatcoll-core";
+  version = "21.0.0";
+
+  src = fetchFromGitHub {
+    owner = "AdaCore";
+    repo = "gnatcoll-core";
+    rev = "v${version}";
+    sha256 = "0jgs2299zfbr6jg5bxlhqizi60si2m8vw7zq6ns4yhr38qqdskqg";
+  };
+
+  nativeBuildInputs = [
+    gprbuild
+    which
+    gnat
+  ];
+
+  # propagate since gprbuild needs to find
+  # referenced GPR project definitions
+  propagatedBuildInputs = [
+    gprbuild # libgpr
+  ];
+
+  makeFlags = [
+    "prefix=${placeholder "out"}"
+    "PROCESSORS=$(NIX_BUILD_CORES)"
+    # confusingly, for gprbuild --target is autoconf --host
+    "TARGET=${stdenv.hostPlatform.config}"
+  ];
+
+  meta = with lib; {
+    homepage = "https://github.com/AdaCore/gnatcoll-core";
+    description = "GNAT Components Collection - Core packages";
+    license = licenses.gpl3Plus;
+    maintainers = [ maintainers.sternenseemann ];
+    platforms = platforms.all;
+  };
+}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 23e5dd061e5b..3e82f2e4fc82 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -15610,6 +15610,8 @@ in
   # A GMP fork
   mpir = callPackage ../development/libraries/mpir {};
 
+  gnatcoll-core = callPackage ../development/libraries/ada/gnatcoll/core.nix { };
+
   gns3Packages = dontRecurseIntoAttrs (callPackage ../applications/networking/gns3 { });
   gns3-gui = gns3Packages.guiStable;
   gns3-server = gns3Packages.serverStable;