Gerrit John Diekema (born March 27, 1859) was a Republican member of the United States House of Representatives from Michigan. He represented Michigan’s 5th Congressional District as a Representative, serving in the U.S. Congress from December 2, 1907, to March 3, 1911. During this period, he was affiliated with the Republican Party and served two terms in office.

Diekema’s tenure in Congress placed him among the historical members of the House from Michigan in the early twentieth century. Serving as a Representative for the 5th District, he participated in national legislative affairs during his time in office, concluding his service in 1911. He is recorded as a former member of Congress, and his career is noted primarily for his role in representing Michigan at the federal level between 1907 and 1911.