diff --git a/src/termdiagram/generators/mermaid_generator.py b/src/termdiagram/generators/mermaid_generator.py
new file mode 100644
index 0000000..7936a72
--- /dev/null
+++ b/src/termdiagram/generators/mermaid_generator.py
@@ -0,0 +1,34 @@
+from typing import List
+from ..models import Module, ClassSymbol
+
+
+class MermaidDiagramGenerator:
+    def generate_class_diagram(self, modules: List[Module]) -> str:
+        lines = ["classDiagram"]
+        lines.append("    direction TB")
+        lines.append("")
+
+        for module in modules:
+            for cls in module.classes:
+                self._render_class(lines, cls)
+                lines.append("")
+
+        for module in modules:
+            for cls in module.classes:
+                self._render_relationships(lines, cls)
+
+        return "\n".join(lines)
+
+    def _render_class(self, lines: List[str], cls: ClassSymbol):
+        class_def = f"    class {cls.name} {{"
+        lines.append(class_def)
+
+        for method in cls.methods:
+            sig = f"({', '.join(method.params)})":""
+            lines.append(f"        +{method.name}{sig}")
+
+        lines.append("    }")
+
+    def _render_relationships(self, lines: List[str], cls: ClassSymbol):
+        for base in cls.bases:
+            lines.append(f"    {base} <|-- {cls.name}")