Mark Joseph Green is an American author, former public official, public interest lawyer, and Democratic politician from New York City. Green was New York City Consumer Affairs Commissioner from 1990 to 1993 and New York City Public Advocate from 1994 to 2002.

The office of New York City Public Advocate is a citywide elected position in New York City, which is first in line to succeed the mayor. The office serves as a direct link between the electorate and city government, effectively acting as an ombudsman, or watchdog, for New Yorkers.