"Ex-Factor" is a song by American recording artist Lauryn Hill for her debut solo studio album The Miseducation of Lauryn Hill (1998). Written and produced by Hill herself, it incorporates elements of R&B, neo soul and hip hop soul. The song features a sample of "Can It Be All So Simple" by Wu-Tang Clan.^[1] It has been claimed to be about Hill's former Fugees groupmate Wyclef Jean.^[2] The song was released as the second single from The Miseducation of Lauryn Hill on December 14, 1998, by Ruffhouse Records and Columbia Records.

Upon its release, "Ex-Factor" received widespread critical acclaim.^[3] The song peaked at number 21 on the US Billboard Hot 100 and at number seven on the Hot R&B/Hip-Hop Songs. Internationally, it peaked within the top five in Iceland and the United Kingdom. It won the Best R&B/Soul Single - Female award at the 2000 Soul Train Music Awards.^[4] Spin named it the third best single of 1999.^[5] In 2020, The Ringer ranked it as the 18th greatest breakup song of all time.^[6] Since its release, the song has been sampled and covered by numerous artists.

"Ex-Factor" was written and produced by Lauryn Hill and it features replayed elements of "Can It Be All So Simple" by Wu-Tang Clan,^[7] which itself samples Gladys Knight & the Pips' cover of Barbra Streisand's "The Way We Were".^[8]

"Ex-Factor" is a soul number which serves as a painful dissection of a failing relationship.^[9][10] The accompaniment is driven by two-chord progressions all throughout its melodic variations.^[9] Its refrain contains soaring harmonies.^[11]

"Ex-Factor", although not as successful as Hill's previous single "Doo Wop (That Thing)", still entered several international charts. It spent 22 weeks on the US Billboard Hot 100, peaking at number 21 on the chart dated April 10, 1999. The song peaked atop the US R&B/Hip-Hop Airplay.^[12] It also charted on the US Hot R&B/Hip-Hop Songs, spending 31 weeks and peaking at number seven on March 13, 1999. It reached number four on the UK Singles Chart and spent 16 weeks on the chart, remaining Hill's biggest hit in the United Kingdom to date.

Since its release, "Ex-Factor" has been sampled by numerous artists in their songs, including rapper Lil B's "Money Over Suckas" (2012), singer Kehlani's "Till the Morning" (2014), singer Omarion's "Show Me" (2014) featuring Jeremih, rapper Drake's "Nice for What" (2018), and rapper Cardi B's "Be Careful" (2018).^[8] Additionally, it has been covered by Beyoncé,^[13] Kelly Clarkson,^[14] John Legend,^[15] and H.E.R.^[16]

Credits are adapted from The Miseducation of Lauryn Hill liner notes.^[7]