"Yakusoku" (約束 / "Promise") is the twenty-sixth single by the Japanese hip-hop group Lead, and was the final single before the release of their studio album The Showcase (2016).

It performed well on Oricon, peaking at number 5 and remaining on the charts for two weeks.

The single was released as a standard CD and three limited edition versions, two of which were CD+DVD combos, each carrying different content.

"Yakusoku" was Lead's final single from their seventh studio album, The Showcase, which was released the following year on June 8.

The DVD portion contained the dance version of "Yakusoku" and the behind-the-scenes footage of the photo shoot for the different single covers.