diff --git a/sqlmesh/magics.py b/sqlmesh/magics.py
index 0a433360df..57dd150af2 100644
--- a/sqlmesh/magics.py
+++ b/sqlmesh/magics.py
@@ -95,6 +95,14 @@ def wrapper(self: SQLMeshMagics, *args: t.Any, **kwargs: t.Any) -> None:
     return wrapper
 
 
+def parse_expand(value: str) -> t.Union[bool, t.List[str]]:
+    if value.lower() == "true":
+        return True
+    if value.lower() == "false":
+        return False
+    return [name.strip() for name in value.split(",") if name.strip()]
+
+
 def format_arguments(func: t.Callable) -> t.Callable:
     """Decorator to add common format arguments to magic commands."""
     func = argument(
@@ -633,8 +641,8 @@ def evaluate(self, context: Context, line: str) -> None:
     @argument("--execution-time", type=str, help="Execution time.")
     @argument(
         "--expand",
-        type=t.Union[bool, t.Iterable[str]],
-        help="Whether or not to use expand materialized models, defaults to False. If True, all referenced models are expanded as raw queries. If a list, only referenced models are expanded as raw queries.",
+        type=parse_expand,
+        help="Whether or not to use expand materialized models, defaults to False. If 'true', all referenced models are expanded as raw queries. If a comma-separated list of model names, only those models are expanded as raw queries.",
     )
     @argument("--dialect", type=str, help="SQL dialect to render.")
     @argument("--no-format", action="store_true", help="Disable fancy formatting of the query.")
@@ -647,6 +655,7 @@ def render(self, context: Context, line: str) -> None:
         render_opts = vars(parse_argstring(self.render, line))
         model = render_opts.pop("model")
         dialect = render_opts.pop("dialect", None)
+        expand = render_opts.pop("expand", False)
 
         model = context.get_model(model, raise_if_missing=True)
 
@@ -655,7 +664,7 @@ def render(self, context: Context, line: str) -> None:
             start=render_opts.pop("start", None),
             end=render_opts.pop("end", None),
             execution_time=render_opts.pop("execution_time", None),
-            expand=render_opts.pop("expand", False),
+            expand=expand,
         )
 
         no_format = render_opts.pop("no_format", False)