What You Won't Do for Love

"What You Won't Do for Love" is a song by American singer-songwriter Bobby Caldwell. It was released in September 1978 as the lead single from his eponymous debut album. It was written by Caldwell and Alfons Kettner, and produced by Ann Holloway. The song has been covered and sampled numerous times, including by Tupac Shakur in the posthumous 1998 hit "Do for Love".

After gaining a reputation in Miami clubs as a talented musician, Caldwell was signed to an exclusive contract with TK Records in 1978 by TK Records president Henry Stone. Heading to the studio, Caldwell recorded his first album, which was given a redo after Stone felt the album was good but "didn't have a hit". Caldwell returned to the studio and came up with the final product, which included "What You Won't Do for Love". The song's horn arrangement was written and recorded by Miami arranger Mike Lewis. The song is in the key of F-sharp minor (although the pitch of the commercial track is slightly flat – i.e., below concert pitch – perhaps due to tape machine speed variation).

Caldwell wanted the song to be the sixth track on the album since he figured his debut album's second track, "My Flame", which featured him playing guitar, would be the hit. However, TK Records felt confident that "What You Won't Do for Love" would be the breakout hit. When it was released to R&B radio, TK Records did their best to hide Caldwell's racial identity, hoping not to alienate their predominantly African American audience. However, when Caldwell began making performances live onstage, demand only increased.

The song would become Caldwell's most successful single and also his signature song, reaching number nine on the US Billboard Hot 100, number six on the Hot Selling Soul Singles chart, and number ten on the Easy Listening chart. In Canada the song reached number 16 on the pop charts, and number 24 on the AOR charts.

According to the broadcast of American Top 40 for the week ending February 3, 1979, the week in which the song debuted at No. 38 on the Top 40, a heart-shaped pressing of the single was the most expensive single up to that point. The heart-shaped single was originally released as a promotional item only, but public demand led to 50,000 copies being pressed in time for Valentine's Day 1979 with a retail price of $7.98—about the price of a full LP album at the time.

After Caldwell's death on March 14, 2023, "What You Won't Do for Love" saw an increase in popularity. In the United Kingdom, the song charted at number 86 on the Singles Downloads Chart Top 100 on March 17, 2023.