Smart was fined $35,000 for questioning the integrity of game officials. Smart complained to referee James Williams about unnecessary ejections.
Kennard was fined $25,000 for directing inappropriate language toward referees.
Both incidents took place in the moments after Houston's 115-96 triumph over the Lakers on Sunday, which lifted the Rockets within 3-1 in the best-of-seven Western Conference first-round playoff series.
The Lakers can advance to the second round with a home victory over the Rockets on Wednesday.
The Rockets avoided a sweep but must win on Wednesday to force a sixth game on Friday at Houston.
A winner-take-all seventh game, if needed, would be played on Sunday in Los Angeles.