Jacob Marstrand (10 August 1848 – 3 June 1935) was a Danish master baker and politician.

His father had just died and his economic situation therefore forced him to give up his dream of becoming an engineer to become a baker's apprentice instead.

In 1885 and 1896, he replaced the old building at Købmagergade 19 with a new one designed by his brother, Sophus Marstrand (1860–1946), who was an architect.

Grundtvig's thoughts from an early age and worked for a while for F. F. Falkenstjerne's [da] folk high school in Frederiksberg and later his magazine.

He wrote biographies of Benjamin Franklin, F. F. Falkenstjerne, C. F. Tietgen, George Stephenson, Bjørnstjerne Bjørnson and Herman Trier (completed and published posthumously by his son Even Marstrand).