What was Diana Ross and the supremes biggest hit song?

Diana Ross and The Supremes' biggest hit song is "You Can't Hurry Love," released in 1966. The track reached number one on the Billboard Hot 100 chart and became one of the defining songs of the Motown era. Its catchy melody and poignant lyrics about love and patience have made it a timeless classic. The Supremes, with Ross as their lead singer, solidified their status as one of the most successful girl groups in music history with this iconic hit.