Walter A. "Pete" Starr, Jr. (1903–1933) was an American lawyer and mountain climber.

A graduate of Stanford University, Starr was a respected lawyer in San Francisco, but he is better known for his abilities as a mountain climber and an explorer of the Sierra Nevada.

In August 1933, he failed to return from a month-long hike in the Minarets. The search that followed, which led to the eventual discovery of his body by Norman Clyde, is one of the most dramatic true tales of the Sierra exploration. His body was buried where it was found.

Starr's final notes were compiled and edited by his father into "Starr’s Guide to the John Muir Trail and the High Sierra Region" which was published a year after his death by the Sierra Club. This book has been edited and revised many times and served hikers and climbers for many years as the standard reference to the trails of the Sierra. A revised version is currently available.