Robert John Duffy (born August 21, 1954) is a former American law enforcement officer and politician who served as the lieutenant governor of New York from 2011 to 2014.

He was elected mayor of the city in November 2005, took office on January 1, 2006, and was reelected in 2009 (unopposed) for a term scheduled to end in 2013.

In May 2010, New York Attorney General Andrew Cuomo selected Duffy as his running mate in the race for Governor.

In April 2020, in the midst of the COVID-19 pandemic, Governor Cuomo appointed Duffy as Special Advisor to coordinate public health and reopening strategy in the Finger Lakes Region.

He was sworn in as the chief of police in 1998[7] after his predecessor, Robert Warshaw, was appointed Associate Director of the Office of National Drug Control Policy.

[8] After William A. Johnson, Jr. announced his retirement, Duffy debated whether to become a candidate for the mayor's office which would have (and did) pit him against the Democratic favorite and city councilman, Wade S. Norwood.

[9] Assemblyman Joseph Morelle called on Duffy to definitively announce or forgo his candidacy or risk running afoul of the state election law prohibiting police officers from soliciting funds for political purposes.

[11] During the opening months of his administration, Mayor Duffy closed down the fast ferry service across Lake Ontario between Toronto and Rochester.

[18] As part of this effort, Duffy was also appointed to lead the Chairman's Committee which included leaders in business, academia, labor, agriculture, nonprofits, and community-based organizations.