Jon Santiago (born April 1, 1982) is an American physician and Democratic politician who served as the Massachusetts state representative for the 9th Suffolk district from 2019 to March 2023.

[6] His 2018 victory in the Democratic primary unseated the chamber's assistant majority leader[7] Byron Rushing, who had represented the district for 35 years, starting in 1983.

[9] Santiago continues to serve as an attending physician in emergency medicine for the Boston Medical Center, arguing that such a job informs his legislation, especially when it comes to matters of public health like the opioid epidemic.

[9] Santiago resigned from the legislature on March 1, 2023, after being appointed by governor Maura Healey to become Massachusetts' Secretary of the Executive Office of Veterans' Services.

[11][12][13] He withdrew from the race on July 13, 2021, and later endorsed Acting Mayor Kim Janey ahead of the preliminary election.