An assist is the action of helping an allied champion kill an enemy champion. Assists can be scored by hitting the enemy within the last 10 seconds before their death. This timer may refresh after contributing subsequently to the kill.
When a champion is killed, the killer gets a certain amount of 
gold, while a reduced amount is shared between all the champions who assisted the kill. See bounty for additional info.
Killing an enemy champion within 
Death from Below grants the last assisting ally full kill gold.
Secondary System[]
Champions may also gain assists on kills by:
- Applying any form of crowd control to the enemy, excluding
Blind and 
Cripple. - Applying a debuff to the enemy, excluding those that reveal.
- Supporting the ally contributing to the kill (e.g. through buffs, heals, or shields).
- Revealing the enemy if they were previously unseen with Ashe's Hawkshot.
Triggering effects with assists[]
- Champion abilities, items and runes that trigger an effect with an assist can be seen on the takedown page.