John M. Summerill Jr. (August 3, 1898 – August 24, 1969) was an American Republican Party politician who served as President of the New Jersey State Senate and as Acting Governor of New Jersey.
He attended Wenonah Academy and is a 1922 graduate of Rutgers University, where he was a four-letter man.
He was elected Republican State Committeeman from Salem County in 1933 and held that post until 1943.
During World War I, Summerill was a member of the Students Army Training Corps.
Summerill was defeated in his 1955 bid for re-election by Democrat John A. Waddington, an Assemblyman.