"Shout Out to My Ex" is a song by British girl group Little Mix. It is the first single from their fourth studio album Glory Days (2016) and premiered on The X Factor live shows on 16 October 2016, becoming the band's fourth number-one single in the United Kingdom. The track was written by Edvard Førre Erfjord, Henrik Michelsen, Camille Purcell, Iain James and Little Mix, with production credits from Erfjord and Michelsen under their production monikers, Electric. The song musically is a dance-pop and power pop song that talks about not showing feelings of regret after breaking up with a boyfriend and wishing well to the new couple.

Idolator's Rachel Sonis described the song as a "kiss-off anthem at its finest" and remarked that it felt like "a confident comeback for the group". Bruno Russell, from The Edge also praised the group, calling the song 'fierce and sassy', although he remarked that previous singles trumped this release. Giving the single 4-stars, Russell said that Shout Out to My Ex composes a "memorable beat and refrain that are well-constructed epitomes of previous successes. This is a very promising teaser of a feistier, more mature album to come".

Billboard ranked "Shout Out to My Ex" at number 58 on their "100 Best Pop Songs of 2016" list.

The song debuted at number one on the UK Singles Chart, achieving 95,000 combined sales to give the band the fourth UK number one of their careers, following "Cannonball" in 2011, "Wings" in 2012 and "Black Magic" in 2015. "Shout Out to My Ex" was also the first UK number one single of 2016 with a female lead, as the three women with number one singles earlier in the year, Kyla, MØ and Halsey, were all featured artists. It stayed at number one the following week, making it Little Mix's second song (after "Black Magic") to spend multiple weeks at number 1. It was also certified silver by the BPI for selling over 200,000 copies in its second week. It spent a third week before being replaced by "Rockabye" by Clean Bandit.

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