John Giraud Agar (June 3, 1856 – September 20, 1935) was a prominent New York lawyer and a leader of the reform political movement.

His son and namesake John G. Agar Jr. died in World War I in October 1918 at St. Mihiel, France.

[2][5] He resigned as school commissioner in 1899, after faulting Tammany Hall for not releasing the funds raised for building and improving schools; removing the requirement for teachers to hold a license; and giving more power to those in politics to choose principals that aligned with their beliefs rather than the best for the job.

[10] In 1916, he was appointed Knight of the Order of St Gregory by Pope Benedict XV and was a trustee of St. Patrick's Cathedral.

[12][13] Agar died September 20, 1935, in Premium Point, New Rochelle, New York, and was buried in Woodlawn Cemetery.