The junior guard averaged 19.9 points, 8.2 assists, and 7.4 rebounds across 38 appearances.
Ionescu led the Ducks to their first-ever Final Four, where they fell to Baylor, the eventual national champions.
The two-time Pac-12 Player of the Year is the all-time NCAA leader in triple-doubles with 18.
Ionescu was projected to go No. 1 in the 2019 WNBA Draft but chose to return for her senior year, citing "unfinished business" in her Players Tribune story published minutes after the WNBA draft declaration deadline.