Óbidos is a municipality in Pará, Brazil located at the narrowest and swiftest part of the Amazon River.

The north of the municipality contains part (7.36%) of the 4,245,819 hectares (10,491,650 acres) Grão-Pará Ecological Station, the largest fully protected tropical forest conservation unit on the planet.

Óbidos, Pará, in Brazil, was the scene of the sinking of Sobral Santos II in September 1981, one of the worst maritime tragedies in the history of the Amazon River.

The riverboat was making its weekly trip between Santarém and Manaus and was claimed to be overcrowded when it sank in Óbidos harbour.

The climate is tropical monsoon (Köppen: Am), with great differences in precipitation according to the seasons.