Hillel Slovak (April 13, 1962–June 25, 1988) was the original guitarist for the band Red Hot Chili Peppers.

Hillel was born in Haifa, Israel and moved to California in 1967. At Fairfax High School, he learned to play guitar. Around the same time he met Anthony Kiedis and Michael Balzary (also known as Flea), whom he taught to play bass guitar. They formed a band and called it "Tony Flow and the Miraculously Majestic Masters of Mayhem," later renaming themselves in 1983 to the Red Hot Chili Peppers.

Hillel, as well as Anthony, soon developed a heroin addiction and left the band for his side project What Is This? After returning to the Red Hot Chili Peppers for the albums, Freaky Styley and The Uplift Mofo Party Plan, Slovak died of a heroin overdose on June 25, 1988.

John Frusciante replaced Hillel as guitarist. The songs "Knock Me Down," "Under the Bridge," "My Lovely Man," and "Behind the Sun" from subsequent Chili Peppers albums were dedicated to Hillel.

Hillel was interred in Mount Sinai Memorial Park Cemetery in Hollywood Hills, California.