The Mornington Peninsula is a peninsula located south-east of Melbourne in Victoria, Australia, surrounded by Port Phillip, Western Port Bay and Bass Strait.

A tourist region with a variety of beaches (both sheltered and open-sea) and seaside resorts, much of the area is now regarded as a part of greater Melbourne. It is known simply as "The Peninsula" to locals and Melburnians alike.

The Melbourne suburb of Frankston is sometimes known as The Gateway to the Peninsula, being where the peninsula joins the mainland on its northern boundary.

The peninsula tapers away and terminates at Point Nepean.