MD 33 between Easton and Saint Michaels was one of the original state roads outlined by the Maryland State Roads Commission in 1909. The state highway was constructed between Easton and Claiborne, the terminus of a ferry to Annapolis, in the late 1910s and early 1920s, and was originally designated MD 17. The portion of the highway between Claiborne and Tilghman Island was constructed as MD 451 in the early 1930s. The state highway was extended north to MD 404 in Matapeake on Kent Island when the western terminus of the ferry from Claiborne was moved to Romancoke in the late 1930s. MD 33 received its present number in a 1940 number swap with present MD 17. Following the shutdown of the ferry, MD 33 was extended west along MD 451 to Tilghman Island and the Romancoke–Matapeake highway was redesignated MD 8. In Easton, MD 33 was extended north along Washington Street in the late 1940s and then along Easton Parkway, now MD 322, in the mid-1960s, before the eastern terminus returned to its present location in the late 1970s.