"Say When" is a song recorded by the American country music group Lonestar, written by then band member John Rich along with Larry Boone and Paul Nelson.

It was released in January 1998 as the third single from their second album Crazy Nights (1997).

Billboard Hot Country Singles & Tracks chart and at number 23 on the Canadian RPM Country Tracks chart.

The song received a positive review in Billboard, saying "This sweet ballad looks sure to accelerate [the band's] momentum at country radio.

Billboard Hot Country Singles & Tracks for the week of January 31, 1998.