"When I'm with You" is a power ballad by Canadian arena rock band Sheriff. It hit number one in the United States in 1989, four years after the band separated.

After the success of When I'm With You, Freddy Curci (Lead Vocalist) and Steve DeMarchi (Lead Guitarist) tried to put Sheriff back together, but the other band members would not cooperate and would not release permission for the use of the band name. This caused Curci and DeMarchi to form the band ALIAS.

The following year, in 1990, ALIAS released a self-titled debut album. It contained the very successful power ballad "More Than Words Can Say", "Haunted Heart", "Waiting for Love" and "Perfect World".

Freddy Curci is listed in the Guinness Book of Records for holding the longest note in a pop song, timed and submitted by a Houston university, at the ending line of "When I'm with You."

Sheriff's keyboardist Arnold Lanni wrote the song after meeting Valeri Brown and falling in love with her. 'I sat down, put my coffee on the piano, tinkled some ivories, and four minutes later 80 percent of the song was written. On Valentine's Day I played the song for Valerie and said, "I don't have anything, this is all I can give you right now. It's yours." Valeri loved the song; two years later she married me.'

Lanni also played the song to his bandmembers in Sheriff. "The band really liked it, so we started playing it live. That was one of the last songs we recorded when we did the record. The producer said, 'Is there anything else?' I said, 'There's this song we play, it's kind of a wimpy song.' So we played it for him and he said 'Yeah, that's kind of nice.'"

"When I’m With You" is also the title of an unrelated song from the 30’s and 40's sung by Shirley Temple and Alice Faye.

"When I'm with You" was originally released as the third single off Sheriff's debut album. It entered the Hot 100 on May 14, 1983, and peaked at number sixty-one four weeks later. Disappointed by the lack of success, the band broke up.

In 1988, a disc jockey in Las Vegas began playing the song, and other stations followed. This encouraged Capitol Records to re-release the song as a single. On February 4, 1989, "When I'm with You" hit number one in the United States.

By that time Lanni and bassist Wolf Hassell had formed a duo named Frozen Ghost, and declined to re-form the group. Sheriff's lead vocalist Freddy Curci and guitarist Steve DeMarchi subsequently formed the band Alias and reached the top of the charts again the following year with the similar number-two hit "More Than Words Can Say".