diff --git a/plugins/by-name/diagram/default.nix b/plugins/by-name/diagram/default.nix
new file mode 100644
index 00000000..dd1e51ad
--- /dev/null
+++ b/plugins/by-name/diagram/default.nix
@@ -0,0 +1,30 @@
+{ lib, ... }:
+lib.nixvim.plugins.mkNeovimPlugin {
+  name = "diagram";
+  packPathName = "diagram.nvim";
+  package = "diagram-nvim";
+
+  maintainers = [ lib.maintainers.GaetanLepage ];
+
+  settingsExample = {
+    integrations = [
+      { __raw = "require('diagram.integrations.markdown')"; }
+      { __raw = "require('diagram.integrations.neorg')"; }
+    ];
+    renderer_options = {
+      mermaid = {
+        theme = "forest";
+      };
+      plantuml = {
+        charset = "utf-8";
+      };
+      d2 = {
+        theme_id = 1;
+      };
+      gnuplot = {
+        theme = "dark";
+        size = "800,600";
+      };
+    };
+  };
+}
diff --git a/tests/test-sources/plugins/by-name/diagram/default.nix b/tests/test-sources/plugins/by-name/diagram/default.nix
new file mode 100644
index 00000000..133f571a
--- /dev/null
+++ b/tests/test-sources/plugins/by-name/diagram/default.nix
@@ -0,0 +1,75 @@
+{
+  empty = {
+    # image.nvim/lua/image/utils/term.lua:34: Failed to get terminal size
+    test.runNvim = false;
+
+    plugins.diagram.enable = true;
+  };
+
+  defaults = {
+    # image.nvim/lua/image/utils/term.lua:34: Failed to get terminal size
+    test.runNvim = false;
+
+    plugins.diagram = {
+      enable = true;
+
+      settings = {
+        renderer_options = {
+          mermaid = {
+            background = null;
+            theme = null;
+            scale = 1;
+            width = null;
+            height = null;
+          };
+          plantuml = {
+            charset = null;
+          };
+          d2 = {
+            theme_id = null;
+            dark_theme_id = null;
+            scale = null;
+            layout = null;
+            sketch = null;
+          };
+          gnuplot = {
+            size = null;
+            font = null;
+            theme = null;
+          };
+        };
+      };
+    };
+  };
+
+  example = {
+    # image.nvim/lua/image/utils/term.lua:34: Failed to get terminal size
+    test.runNvim = false;
+
+    plugins.diagram = {
+      enable = true;
+
+      settings = {
+        integrations = [
+          { __raw = "require('diagram.integrations.markdown')"; }
+          { __raw = "require('diagram.integrations.neorg')"; }
+        ];
+        renderer_options = {
+          mermaid = {
+            theme = "forest";
+          };
+          plantuml = {
+            charset = "utf-8";
+          };
+          d2 = {
+            theme_id = 1;
+          };
+          gnuplot = {
+            theme = "dark";
+            size = "800,600";
+          };
+        };
+      };
+    };
+  };
+}