diff --git a/maintainers/maintainer-list.nix b/maintainers/maintainer-list.nix
index 8e6e1d2b93ac..d85109f2dd0d 100644
--- a/maintainers/maintainer-list.nix
+++ b/maintainers/maintainer-list.nix
@@ -9663,6 +9663,11 @@
     githubId = 293586;
     name = "Adam Gamble";
   };
+  gamebeaker = {
+    github = "gamebeaker";
+    githubId = 9269847;
+    name = "gamebeaker";
+  };
   gamedungeon = {
     github = "GameDungeon";
     githubId = 60719255;
diff --git a/pkgs/by-name/mo/modelio/package.nix b/pkgs/by-name/mo/modelio/package.nix
new file mode 100644
index 000000000000..dad1c78bd655
--- /dev/null
+++ b/pkgs/by-name/mo/modelio/package.nix
@@ -0,0 +1,136 @@
+{
+  lib,
+  stdenvNoCC,
+  fetchurl,
+  dpkg,
+  makeWrapper,
+  autoPatchelfHook,
+  wrapGAppsHook3,
+  gtk3,
+  glib,
+  libsecret,
+  libx11,
+  libxtst,
+  openjdk11,
+  webkitgtk_4_1,
+  glib-networking,
+  imagemagick,
+}:
+
+let
+  # SWT 3.120 hardcodes dlopen("libwebkit2gtk-4.0.so.37") but nixpkgs
+  # only ships webkitgtk_4_1 (soname libwebkit2gtk-4.1.so.0).
+  webkitCompat = stdenvNoCC.mkDerivation {
+    name = "webkitgtk-4.0-compat";
+    dontUnpack = true;
+    installPhase = ''
+      mkdir -p $out/lib
+      ln -s ${webkitgtk_4_1}/lib/libwebkit2gtk-4.1.so.0 $out/lib/libwebkit2gtk-4.0.so.37
+    '';
+  };
+in
+stdenvNoCC.mkDerivation (finalAttrs: {
+  pname = "modelio";
+  version = "5.4.1";
+  # Using .deb package instead of building from source as the build process uses eclipse gui as a necessary build step.
+  # Building from source steps: https://github.com/ModelioOpenSource/Modelio/wiki/Build-Modelio-Index
+  # I was unsuccessful in the attempt to build it via cli.
+  src = fetchurl {
+    url = "https://github.com/ModelioOpenSource/Modelio/releases/download/v${finalAttrs.version}/modelio-open-source-${finalAttrs.version}_amd64.deb";
+    hash = "sha256-cg7ruIYpOgz2nfax37M8sUs89Qvbb5PMudyR0ZNiURo=";
+  };
+
+  nativeBuildInputs = [
+    dpkg
+    makeWrapper
+    autoPatchelfHook
+    wrapGAppsHook3
+    imagemagick
+  ];
+
+  buildInputs = [
+    gtk3
+    glib
+    libsecret
+    libx11
+    libxtst
+  ];
+
+  strictDeps = true;
+  __structuredAttrs = true;
+
+  unpackPhase = ''
+    runHook preUnpack
+    dpkg-deb --extract $src .
+    runHook postUnpack
+  '';
+
+  dontConfigure = true;
+  dontBuild = true;
+
+  installPhase = ''
+    runHook preInstall
+
+    rm -rf usr/lib/modelio-open-source5.4/jre
+
+    mkdir -p $out/opt/modelio $out/bin
+    cp -r usr/lib/modelio-open-source5.4/* $out/opt/modelio
+
+    # Remove upstream's blanket TLS error suppression
+    substituteInPlace $out/opt/modelio/modelio.ini \
+      --replace-fail "-Dorg.eclipse.swt.internal.webkitgtk.ignoretlserrors=true" ""
+
+    # change dark theme to light theme as the text isn't readable in dark themes GTK_THEME "Adwaita:light" isn't enough
+    # https://github.com/ModelioOpenSource/Modelio/issues/59
+    cp $out/opt/modelio/plugins/org.eclipse.ui.themes_1.2.1200.v20201112-1139/css/{e4_basestyle,e4-dark_linux}.css
+
+    # --set GTK_THEME "Adwaita:light" as the text isn't readable in dark themes
+    # https://github.com/ModelioOpenSource/Modelio/issues/59
+    makeWrapper $out/opt/modelio/modelio $out/bin/modelio \
+      --prefix PATH : "${openjdk11}/bin" \
+      --set JAVA_HOME "${openjdk11.home}" \
+      --set GDK_BACKEND "x11" \
+      --set GTK_THEME "Adwaita:light" \
+      --set SWT_GTK3 "1" \
+      --set SWT_WEBKIT2 "1" \
+      --set UBUNTU_MENUPROXY "0" \
+      --set LIBOVERLAY_SCROLLBAR "0" \
+      --prefix GIO_EXTRA_MODULES : "${glib-networking}/lib/gio/modules" \
+      --prefix LD_LIBRARY_PATH : "${
+        lib.makeLibraryPath [
+          gtk3
+          glib
+          webkitCompat
+          glib-networking
+        ]
+      }"
+
+    mkdir -p $out/share/applications
+    cp usr/share/applications/modelio-open-source5.4.desktop $out/share/applications/modelio.desktop
+    substituteInPlace $out/share/applications/modelio.desktop \
+      --replace-fail "Exec=/usr/bin/modelio-open-source5.4" "Exec=$out/bin/modelio" \
+      --replace-fail "Icon=modelio-open-source5.4" "Icon=modelio"
+
+    mkdir -p $out/share/icons/hicolor/scalable/apps
+    cp usr/share/icons/hicolor/scalable/apps/modelio-open-source5.4.svg \
+       $out/share/icons/hicolor/scalable/apps/modelio.svg
+
+    for size in 16 32 48 64 128 256 512; do
+      mkdir -p $out/share/icons/hicolor/"$size"x"$size"/apps
+      magick -background none $out/share/icons/hicolor/scalable/apps/modelio.svg -resize "$size"x"$size" $out/share/icons/hicolor/"$size"x"$size"/apps/modelio.png
+    done
+
+    runHook postInstall
+  '';
+
+  meta = {
+    homepage = "https://www.modelio.org/";
+    changelog = "https://github.com/ModelioOpenSource/Modelio/releases/tag/v${finalAttrs.version}";
+    description = "Open-source UML, BPMN, ArchiMate and SysML modeling environment";
+    sourceProvenance = [ lib.sourceTypes.binaryNativeCode ];
+    license = lib.licenses.agpl3Only;
+    maintainers = with lib.maintainers; [ gamebeaker ];
+    platforms = [ "x86_64-linux" ];
+    mainProgram = "modelio";
+  };
+})