Hammon will become the first female coach in the NBA history.
In July, the Los Angeles Clippers named Natalie Nakase an assistant coach for summer league games, but she is not expected to be named an assistant for the regular season.
Hammon currently plays for the San Antonio Stars in the WNBA. She will retire as a player when the season comes to an end.
A 16-year WNBA veteran, Hammon ranks seventh in WNBA history in points (5,809), fourth in assists (1,687) and sixth in games (445).
"I very much look forward to the addition of Becky Hammon to our staff," said Spurs head coach Gregg Popovich. "Having observed her working with our team this past season, I'm confident her basketball IQ, work ethic and interpersonal skills will be a great benefit to the Spurs."
A six-time WNBA All-Star, Hammon has spent the last eight seasons with the Stars after going undrafted in the 1999 WNBA Draft and spending the first eight years of her career with the New York Liberty.
She is the Stars' all-time leader in assists (1,112) and 3-point field goals made (493) while ranking second in franchise history in points (3,442) and games (218).
In her WNBA career, Hammon has averages of 13.1 points, 3.8 assists and 2.5 rebounds. She has earned All-WNBA First Team honors twice (in 2007 and 2009) and was named to the All-WNBA Second Team in 2005 and 2008.