Belfast Dock was a constituency of the Parliament of Northern Ireland.

It was created in 1929 when the House of Commons (Method of Voting and Redistribution of Seats) Act (Northern Ireland) 1929 introduced first-past-the-post elections throughout Northern Ireland.

Consequently, the constituency was almost identical to the current New Lodge ward.

The constituency was one of the most marginal in the Northern Ireland Parliament changing hands at every election until 1965.

In every election from 1933 to 1965 the incumbent member lost his seat.