Earl Stevens (born November 15, 1967) better known by his stage name E-40, is an American rapper, entrepreneur, and investor from Vallejo, California. He is a founding member of the rap group The Click, and the founder of Sick Wid It Records. He has released twenty-two studio albums to date, appeared on numerous movie soundtracks, and has also done guest appearances on a host of other rap albums. Initially an underground artist, his 1995 solo album In a Major Way opened him up to a wider audience. Beginning in 1998, he began collaborating with more mainstream rappers outside of the Bay Area. He rose to even higher mainstream popularity in 2006 with his single "Tell Me When to Go" which was produced by Lil Jon.

E40 may refer to:

• Nimzo-Indian Defense, Encyclopaedia of Chess Openings code
• European route E40, a road extending from France to Kazakhstan
• E-40, a rapper
• GE E40, a locomotive
• a name for the fuel blend of 40% ethanol and 60% gasoline
• E40 screw, a type of Edison screw
• HMS E40, a British E class submarine