HMS Plantagenet was a 74-gun third rate ship of the line of the Royal Navy, launched on 22 October 1801 at Woolwich. She was designed by Sir William Rule as one of the 'large class' 74s, and was the only ship built to her draught. As a large 74, she carried 24-pounder guns on her upper gun deck instead of the 18-pounder guns found on the middling and common class 74s.

Sir William Rule was a shipbuilder and designer to the Royal Navy who rose to be Surveyor of the Navy.