"Lover" is a song written and recorded by the American singer-songwriter Taylor Swift and the title track of her seventh studio album (2019). Swift conceived it as a timeless love song that could be played at a wedding reception; the lyrics are about an intimate and committed relationship, and the bridge draws on the bridal rhyme "Something old". Produced by Swift and Jack Antonoff, "Lover" combines country and indie folk over a waltz tempo. It has an acoustic-guitar-driven balladic production consisting of snare drums, piano, pizzicato strings, and dense reverb. Republic Records released "Lover" for download and streaming on August 16, 2019, and to US radio the next month.

Swift and Drew Kirsch directed the music video, which was released on August 22, 2019; it follows a couple living inside a dollhouse in a snow globe. Republic Records released three alternate versions of "Lover": a duet remix featuring the Canadian singer Shawn Mendes, an orchestral "First Dance Remix" based on Swift's performance at the 2019 American Music Awards, and a live version recorded at her 2019 City of Lover concert. During promotion of Lover in 2019, Swift performed the song on televised events such as the MTV Video Music Awards and Saturday Night Live. She included it in the set list of her sixth concert tour, the Eras Tour (2023–2024).

Music critics lauded Swift's songwriting on "Lover" and commented that it showcased emotionally engaging lyrics and a romantic production. Some appreciated the acoustic production that was reminiscent of Swift's early-career albums. Publications including Billboard, Complex, and Pitchfork featured the song on their 2019 year-end lists. It was Swift's first solo-written track nominated for Song of the Year at the 2020 Grammy Awards, and its video received two MTV Video Music Award nominations. The single peaked within the top 10 on charts and received multi-platinum certifications in Australia, Canada, New Zealand, and the United States.