Donald Thomas Valentine (June 26, 1932 – October 25, 2019) was an American venture capitalist who concentrated mainly on technology companies in the United States.

"[4] Valentine grew up in the Bronx, New York, was Catholic, and came from a family with Danish background.

from Fordham University,[6] Valentine began his career as a sales engineer at Raytheon.

He left and joined National Semiconductor, working as a senior sales and marketing executive.

[11] Sequoia was one of the original investors of Apple Computer and Atari after Valentine met Steve Jobs when he was a line engineer for Atari,[12][13] and in 1978, Sequoia invested $150,000 in Apple Inc.[14] Sequoia Capital has also made early investments in companies including LSI Logic, Oracle Corporation, Cisco, Electronic Arts, Google, YouTube and many others.