The Warriors' lead was cut to five points in the fourth, but they responded by scoring eight straight points, building the lead to 96-83 with just under 2 1/2 minutes left.
After scoring 20-plus points in the first two games, Kings center DeMarcus Cousins made 2 of 10 shots and had eight points and nine rebounds.
Thomas scored inside and was fouled on the play by Curry. Thomas made the free throw to complete the three-point play, cutting the lead to 88-83 with 4:43 left.
After two home victories to open the preseason, the Kings looked sloppy offensively throughout the game. They committed 23 turnovers and shot 33 perccent.
The Warriors enjoyed an energized first half, outplaying the Kings. Curry scored 12 points and Thompson had 10. Thomas scored 10 points for Sacramento, which shot 34 percent.
Earlier in the day, the Kings announced that they exercised the 2013-14 contract options of Cousins and guard Jimmer Fredette.
Pau Gasol says he is heading to Rio de Janeiro for the Olympic Games, noting that his commitment to the Spanish national team is greater than his fears about the Zika virus.
Marc Stein provides an update on Kevin Durant's free agent status, with the Warriors, Spurs and Thunder setting up meetings. Stein believes Thunder have a great shot to keep him, but they still have to make their pitch.
Kevin Durant, the top prize of the 2016 free-agent market, will sit down first with the Warriors, Spurs and Thunder, sources said.