The Portrait of Marc Isambard Brunel is a portrait painting by the English artist James Northcote depicting the French-born British engineer Marc Isambard Brunel.

Brunel was a pioneering engineer of the Regency era known particularly for his creation of a block-making machine during the Napoleonic Wars and his later construction of the Thames Tunnel, a project which also involved his son Isambard Kingdom Brunel.

He was paid twenty guineas for the portrait, which was commissioned by Thomas Mudge, Brunel's business partner and the brother-in-law of his wife.

[1] The work shows Brunel in a velvet coat with a model of one of his block-making machines in the background.

[2] Today it is part of the collection of the National Portrait Gallery in London having been donated by the sitter's grandson Henry Marc Brunel in 1895.