Sugarloaf Mountain (Portuguese: Pão de Açúcar, pronounced [ˈpɐ̃w dʒ(i) ɐˈsukaʁ]) is a peak situated in Rio de Janeiro, Brazil, at the mouth of Guanabara Bay on a peninsula that juts out into the Atlantic Ocean. Rising 396 m (1,299 ft) above the harbor, the peak is named for its resemblance to the traditional shape of concentrated refined loaf sugar. It is known worldwide for its cableway and panoramic views of the city and beyond.

The mountain is one of several monolithic granite and quartz mountains that rise straight from the water's edge around Rio de Janeiro. Geologically, it is considered part of a family of steep-sided rock outcroppings known as non-inselberg bornhardts.

The mountain is protected by the Sugarloaf Mountain and Urca Hill Natural Monument, created in 2006. This became part of a World Heritage Site declared by UNESCO in 2012.