Swifties are the fandom of the American singer-songwriter Taylor Swift. Regarded by journalists as one of the largest and most devoted fanbases in music, Swifties are known for their high levels of participation, community, and cultural impact on the music industry and popular culture. They are a subject of widespread coverage in the mainstream media.

Critics have opined that Swift has redefined artist–fandom relationships by establishing an intimate connection with Swifties. She has frequently engaged with, helped, credited and prioritized her fans, who have offered unprecedented support and interest in her works irrespective of her wavering reception in the media. They continued to support Swift through her genre transitions, unanticipated artistic pivots, and her highly publicized controversies such as the 2019 masters dispute, while instigating the political scrutiny of Ticketmaster that led to the implementation of various laws and stimulating economic growth with the Eras Tour. Journalists consider Swifties as a significantly influential voting bloc, especially in the politics of the United States.

Swift's releases, promotional efforts, and fashion have garnered attention for incorporating Easter eggs and clues that are decoded by Swifties and considered part of her musical universe. They have also been a subject of criticism, with some fans displaying disregard for Swift's privacy by publicizing her real-time locations and verbally abusing individuals, including celebrities, who malign Swift. On the other hand, some Swifties criticize Swift herself for her lifestyle and professional choices, which journalists disapprove as a parasocial relationship.

Cultural analyses have variably described Swifties as a community of interest, a subculture, and a near-metaverse, while academics have studied them for their consumerism, content creation, social capital, collective effervescence, organizing prolificacy, and interpersonal relationships. The word "Swiftie(s)" was added to the Oxford Dictionary of English in 2023.

Taylor Swift began writing, recording and releasing country music in 2006. Before releasing her debut single, "Tim McGraw" (2006), Swift had been using social networking websites. She was one of the first country artists to use the Internet as a marketing tool for her music, predominantly promoting herself on Myspace and connecting with listeners who liked her music when it played on the radio. She created her MySpace account on August 31, 2005, a day before her then-label, Big Machine Records, was inaugurated. Swift's songs on MySpace collected more than 45 million listens, which Scott Borchetta, the label CEO, provided to "skeptical" country radio programmers to convince them of existing fans for Swift's songs.

Swift released her self-titled debut studio album in the United States in October 2006. After selling 40,000 copies in its first week, it became a sleeper hit as its sales remained consistent over time, reaching one million copies in November 2007. It garnered its highest sales week in January 2008, with 187,000 copies. This sleeper success contributed to a rapid increase in Swift's notability within and beyond the country music scene. Taylor Swift spent 24 weeks at the number-one spot of the U.S. Top Country Albums chart and became the longest-running album from the 2000s decade on the all-genre Billboard 200. Her follow-up album, Fearless, was released in November 2008 and became the best-selling album of 2009. It achieved significant international success beyond the Anglosphere, where country music was then not popular, and its singles "Love Story" and "You Belong with Me" became crossover successes on pop radio, catapulting Swift to mainstream fame and widening her audience. The success planted dedicated fanbases for Swift in overseas markets such as the United Kingdom, Ireland, Brazil, Taiwan, India, Indonesia, Egypt, and Japan. Her subsequent albums, which saw her experiment with pop, rock, electronic, folk, and alternative styles, helped enlarge her fanbase and diversify its demographics in the following decades.

The word "Swiftie" for a Swift fan gained popularity in the late 2000s. Etymologically, the word is formed from Swift's name and the suffix "ie", which is often used in diminutives to imply affection. Swift stated in a 2012 Vevo interview that her fans call themselves "Swifties", which she found "adorable". Swift filed the term for trademark in March 2017. In 2023, Oxford Dictionary of English defined Swiftie as a noun meaning "an enthusiastic fan of the singer Taylor Swift." As per the dictionary, some words that collocate with Swiftie in popular usage are "fandom", "die-hard", "hardcore" and "self-proclaimed". According to Dictionary.com, the term Swiftie often implies that the person is "a very passionate and loyal fan—as opposed to just a casual listener."

Swift maintains a close relationship with Swifties, to whom many journalists attribute her cultural influence. To The Washington Post, Swift and Swifties are "all part of one big friend group". She has "revolutionized" the relationship a celebrity can have with fans, according to The New York Times. Many fans feel connected to her as they "have grown up with her and her music." Lora Kelley of The Atlantic stated that Swift "understands the power of the group experience." Her connection with fans is considered unique for artists of her stature; she has interacted with them on social media, sent them gifts, hand-selected them to attend intimate concerts or meet-and-greets, made surprise visits, participated in some of their functions (such as a wedding or a bridal shower), and gifted free tickets to disadvantaged or medically ill fans. Swift's habit of lurking her fans online has been referred to as "Taylurking" by the fans.