Porsha Phillips played for Redan High School in her hometown of Stone Mountain, Georgia. While at Redan, Phillips averaged 18.8 points, 5.3 rebounds and 3.8 blocked shots as a senior to earn elite status as a Women's Basketball Coaches Association (WBCA), USA Today, Parade and McDonald's All-American. All four organizations honor the top high school players in the country.
For her career Phillips led Redan and head coach Rhonda Malone to a 104–27 record, including two state runner-up finishes. She posted 1,624 points and 837 rebounds during her career as well.
Phillips, a three-time DeKalb County Player of the Year, was ranked as the eighth overall recruit in the country by Blue Star Girls Report and 15th overall, and the second highest ranked forward by Roundball Journal.