Passamaquoddy is the name of a tribe of native Americans who live in the state of Maine in northeastern New England, and the Atlantic province of New Brunswick, Canada.

Like virtually all such tribes, the Passamaqoddy have no written history from before the arrival of Europeans, but do have an extensive oral tradition. They had a nomadic existence in the well-watered woods and mountains of the region, hunting inland in the winter, and fishing on the coast and islands in the summer.

They were moved off land repeatedly by European settlers, and eventually limited to the current Indian Township Reservation is eastern Washington County, Maine, and also in St. Stephens, New Brunswick.

The Passamaquoddy population in Maine is about 2,500 people, with more than half of adults still speaking the Passamaquoddy language.

The tribe may be best known outside the region for Passamaquoddy vs. Morton, a 1975 land claims lawsuit that opened the doors for successful land claims for many tribes, giving federal recognition and millions of dollars to purchase trust lands.