diff --git a/.changeset/fluffy-news-tan.md b/.changeset/fluffy-news-tan.md
new file mode 100644
index 000000000..c7e1c8f64
--- /dev/null
+++ b/.changeset/fluffy-news-tan.md
@@ -0,0 +1,5 @@
+---
+'@myst-theme/providers': patch
+---
+
+Make theme optional on ThemeProvider
diff --git a/packages/providers/src/theme.tsx b/packages/providers/src/theme.tsx
index e438e5a4b..3d77555aa 100644
--- a/packages/providers/src/theme.tsx
+++ b/packages/providers/src/theme.tsx
@@ -60,14 +60,14 @@ const prefersLightMQ = '(prefers-color-scheme: light)';
 
 export function ThemeProvider({
   children,
-  theme: startingTheme,
+  theme: startingTheme = Theme.light,
   renderers,
   Link,
   top,
   NavLink,
 }: {
   children: React.ReactNode;
-  theme: Theme | null;
+  theme?: Theme;
   renderers?: Record<string, NodeRenderer>;
   Link?: Link;
   top?: number;