Trevor Joseph Rosen (born February 18, 1975) is an American country music songwriter and musician.

He met Matthew Ramsey soon after arriving and the two began collaborating, eventually becoming founding members of the hit supergroup, Old Dominion.

In the year following, Rosen co-wrote 9 of the 12 songs for Old Dominion's second studio album, Happy Endings, including the Number One hits, "No Such Thing as a Broken Heart" and "Written in the Sand.".

Rosen's songwriting accolades expand well beyond Old Dominion’s success, as he has written multiple number one songs including Dierks Bentley’s"Say You Do",[5] The Band Perry's Better Dig Two,[6] Blake Shelton’s Sangria[7] and the longest charting number one song in Country Aircheck history, William Michael Morgan’s I Met A Girl.

He has also written songs recorded by Jake Owen, Scotty McCreery, Keith Urban, Craig Morgan, Dustin Lynch, Randy Houser, and Randy Rogers Band as well as songs performed on the ABC show Nashville.