John Randolph Thayer (March 9, 1845 – December 19, 1916) was a representative from Massachusetts.

He was born in Douglas, Massachusetts, and attended the common schools and Nichols Academy in Dudley.

He was admitted to the bar in 1871 and commenced practice in Worcester, Massachusetts.

[1][3] After unsuccessfully running for district attorney in 1876, he was elected a member of the Massachusetts House of Representatives in 1880 and 1881.

[4] Thayer did not seek reelection in 1904 but resumed his law practice in Worcester.