This was written and sung by group leader Eugene Record. The other three Chi-Lites (pronounced "Shy-Lites") contributed a few wordless harmonies and one line per verse.
Of the many cover versions (by Paul Young, Leo Sayer, Smokey Robinson among others), nearly everyone swipes the harmonica part, proof of how key it is to the song's arrangement.
Suggestion credit: Charles - Charlotte, NC for above 2
According to the Independent newspaper from July 25, 2005, Eugene Record initially dismissed this song. Record is quoted as saying, "I gave Carl Davis 7 songs on a tape and he called me to say there's a #1 tune on there. I named them all before 'Oh Girl' and I thought he was kidding."
Suggestion credit: Edward Pearce - Ashford, Kent, England