Generations III and IV
Serene Grace will double the chance of a move having an additional effect. For example, Psychic will have a 20% chance of lowering the target's Special Defense stat instead of its usual 10% chance, and Rock Smash will always lower an opponent's Defense by 1 level, as opposed to having a 50% chance of doing so. The 10% flinch chance due to King's Rock and Razor Fang is unaffected by Serene Grace. Serene Grace has no effect on status moves.
Generation V onward
Serene Grace boosts the 10% flinch chance due to King's Rock or Razor Fang to 20%.
Serene Grace is cumulative with the rainbow produced by using Fire Pledge and Water Pledge on the same turn (causing secondary effect probabilities to be multiplied by 4 if both modifiers are present), except that moves with a chance to flinch will only have that chance doubled once. Due to the way certain secondary effects are handled, this can lead to an overflow glitch.
Serene Grace does not increase the probabilities for additional effects of G-Max Replenish or G-Max Snooze.
The table below lists the moves affected by Serene Grace, as well as the Pokémon that can have Serene Grace and learn those moves.
Although the following moves are affected by the Ability, they currently cannot be learned by any Pokémon with Serene Grace. They may, however, be called via Metronome, Mirror Move, Copycat, or Mimic, or be used by a Pokémon that gained Serene Grace by Trace or a move such as Skill Swap or Role Play.
Outside of battle
Serene Grace has no effect outside of battle.