The funds will be used improve the school’s computer science department, which will add 400 undergraduate students and 200 graduate students.
The faculty will grow to 70 members from 45.
Siebel received a bachelor’s degree in history and master’s degrees in business administration and computer science from the university.
With an estimated worth of $1.5 billion, he ranks 159th on Forbes’s list of richest Americans.
Siebel Systems, based in San Mateo, Calif., produces e-business applications software.