Ian Gillan (born 19 August 1945) is an English singer who is best known as the lead singer and lyricist for the rock band Deep Purple. He is known for his powerful and wide-ranging singing voice.

Initially influenced by Elvis Presley, Gillan started and fronted several local bands in the mid-1960s, and eventually joined Episode Six when their original singer left. He first found widespread commercial success after joining Deep Purple in 1969. He resigned from the band in June 1973, having given a lengthy notice period to their managers. After a short time away from the music business, he resumed his music career with solo bands the Ian Gillan Band and Gillan, before a year-long stint as the vocalist for Black Sabbath in 1983. The following year, Deep Purple reformed and two more successful albums followed before he left in 1989. He returned to the group in 1993, and has remained its lead singer ever since.

In addition to his main work—performing with Deep Purple and other bands during the 1970s and 1980s—he sang the role of Jesus in the original recording of Andrew Lloyd Webber's rock opera Jesus Christ Superstar (1970), performed in the charity supergroup Rock Aid Armenia, and engaged in a number of business investments and ventures, including a hotel, a motorcycle manufacturer, and music recording facilities at Kingsway Studios.

More recently, he has performed solo concerts concurrently with his latter career in Deep Purple, and his work and affinity with Armenia, combined with his continued friendship with Tony Iommi since his brief time in Black Sabbath, has led him to form the supergroup WhoCares with Iommi. His solo career outside of Deep Purple was given a comprehensive overview with the Gillan's Inn box set in 2006.