Portsmouth is a city in Dominica in the Caribbean.

Portsmouth is the former capital and, with 2,977 inhabitants, the second largest town of Dominica. It lies on the Indian River in the north of the island, part of the Saint John Parish. Cabrits National Park is located on a peninsula in the the town. Portsmouth has its own sea port. In 1760, it was supposed to become the capital of Dominica, but after malaria broke out there in the same year, Roseau was chosen instead.

The Ross University School of Medicine, part of DeVry University, which has over 1,000 students mainly from US and Canada, is located in Portsmouth. The existence is a major economy resource for the local people, especially landlords who rent out their apartments to the students. Inside the school, there is a Subway restaurant, which is one of three on the island.

There is also a Saturday market in the city where locals sell their fresh produce.