Gase, 40, posted a 23-25 record in three seasons with the Dolphins. He served as the Denver Broncos' and Chicago Bears' offensive coordinator before being hired in 2016 for his first head coaching job.
Gase began his NFL coaching career in 2003 as a scouting assistant with the Detroit Lions. He was promoted to offensive assistant in 2005 before becoming the Lions' quarterback coach in 2007. Gase became an offensive assistant with the San Francisco 49ers in 2008 before joining the Broncos in 2009 as a wide receivers coach.
The Dolphins posted a 10-6 record in Gase's first season, but failed to make the postseason in 2017 and 2018. Miami ranked 31st in offensive yards, 30th in point differential and 29th in yards allowed this season.
The AFC East squad has yet to officially announce Gase's departure.