The Casa de Estudillo, also known as the Estudillo House, is a historic adobe house in San Diego, California, United States. It was constructed in 1827 by José María Estudillo and his son José Antonio Estudillo, early settlers of San Diego and members of the prominent Estudillo family of California, and was considered one of the finest houses in Mexican California. It is located in Old Town San Diego State Historic Park, and is designated as both a National and a California Historical Landmark in its own right.

Hazel Wood Waterman (1865–1948) was an early 20th century American architect working in an Arts and Crafts—inspired style in southern California. She undertook the first major renovation of Estudillo House, which is one of the oldest surviving examples of Spanish architecture in California.