There are at least three artists names Sir:
SiR (born Sir Darryl Farris on November 5th, 1986) is an American singer, songwriter and record producer from Inglewood, California. He is currently signed to Top Dawg Entertainment and has released three studio albums; "Seven Sundays" (2015), "November" (2018) and "Chasing Summer" (2019).
SIR (Sanspo Idol Reporter) is a Japanese idol group formed in 2011. The group is split into Team ST and Team AT. Prior to 2020, they were split into Team Emperor, Team Devil, and Team Angel.
Sir was a slowcore band formed in 1998 in Melbourne, Australia. The group initially consisted of husband-and-wife Jesse Jackson Shepherd on keys/vox and Elizabeth Downey on strums/vox. After their separation, Jesse reformed the band with a revolving group of musicians, releasing 2007's The Brando Room. Jane Badler collaborated on with the band, singing on 2008's The Devil Has My Double and 2011's Tears Again.