Benjamin Mackall IV (August 14, 1745 – 1807) was an American planter, lawyer, and jurist from Calvert County, Maryland.

Although not the eldest son, he did inherit a small farm in Calvert County from his father, which he expanded to 1,620 acres (7 km2) by his death.

He was a member of all the sessions of the revolutionary house known as the Annapolis Convention, including the one that adopted the Maryland Constitution of 1776.

At one of these he gained his name of Benjamin Mackall IV, since he was the fourth of that name to sign the Declaration of Rights of Freeman of Maryland in 1775.

He died at home in 1807 on his plantation known as God's Grace in Calvert County, and was buried in a family plot there.