Squad is a term used by the media to describe Taylor Swift's large yet close-knit circle of friends. The fact that some of her friends are successful models, actresses, and singers has also attracted attention.
Taylor's squad includes actresses such as Jamie King, Hailee Steinfeld, Sarah Hyland, and Emma Stone. Singers such as Lorde, Selena Gomez, Ed Sheeran. Models including Martha Hunt, Lily Aldridge, Karlie Kloss, Gigi Hadid, and Cara Delevingne are also a part of the squad. Many of the people in the squad have even appeared in Taylor's Bad Blood music video as well as onstage with Taylor at various stops during her 1989 World tour. Several were with Taylor at the 2015 MTV Video Music Awards and have stood by her whenever she has been blasted by others such as singer/actress Miley Cyrus.
Cosmopolitan magazine has created a timeline for when all of her squad members joined. 
Members Of The Squad
Selena Gomez 
Gigi Hadid 
Cara Delevingne 
HAIM (Este, Danielle, and Alana Haim)
Hailee Steinfeld