The Sparks, 11-2 at Staples Center this season, became the fourth WNBA team to clinch a spot in the playoffs.
Eleven of the 12 players for the Sparks scored, including six in double figures. Chiney Ogwumike scored 15 points, Tierra Ruffin-Pratt added 11, and Chelsea Gray, Riquna Williams and Kalani Brown each had 10 for Los Angeles (17-10).
Williams returned from a 10-game suspension stemming from a domestic violence incident. She was 4 of 12 from the field, 1 of 8 from distance, in 28 minutes.
Kelsey Mitchell scored 14 points for Indiana (9-19), which has lost three straight. Indiana was outscored 29-13 in the second quarter and 27-11 in the third.