Peter Thomas Gaynor (born 1958) is an American Certified Emergency Manager who served briefly as acting Secretary of Homeland Security under President Trump.

[3] Gaynor, who grew up in Warwick, Rhode Island, graduated from Pilgrim High School in 1977, and subsequently enlisted in the Marine Corps.

[7] From March 2008 to December 2014, Gaynor was the director of the Providence Emergency Management Agency and Office of Homeland Security.

Gaynor oversaw response and recovery efforts to blizzards, floods, tropical storms and public health emergencies.

Gaynor was in charge of the agency's recovery efforts for many disasters, including the California wildfires, tornado outbreaks, severe storms, flooding in the Midwest and the Puerto Rico earthquakes.