As we understand Levitation, even involuntary movement by an opponent can trigger an Opportunity Attack.
Does that mean that even the wizard who cast the spell get an Opportunity Attack against an opponent they Levitate away from themselves?
Role-playing Games Stack Exchange is a question and answer site for gamemasters and players of tabletop, paper-and-pencil role-playing games. It only takes a minute to sign up.
Sign up to join this communityAs we understand Levitation, even involuntary movement by an opponent can trigger an Opportunity Attack.
Does that mean that even the wizard who cast the spell get an Opportunity Attack against an opponent they Levitate away from themselves?
From the PHB rules on opportunity attacks:
You can avoid provoking an opportunity attack by taking the Disengage action. You also don’t provoke an opportunity attack when you Teleport or when someone or something moves you without using your Movement, action, or reaction. For example, you don’t provoke an opportunity attack if an explosion hurls you out of a foe’s reach or if gravity causes you to fall past an enemy.
So if something else moves an opponent (e.g. a Levitation spell), they do not trigger any Opportunity attacks during that movement.
You appear to have taken "even involuntary movement by an opponent can trigger an Opportunity Attack" as a given - this is not the case.
You can avoid provoking an opportunity attack by taking the Disengage action. You also don’t provoke an opportunity attack when you teleport or when someone or something moves you without using your movement, action, or reaction. For example, you don’t provoke an opportunity attack if an explosion hurls you out of a foe’s reach or if gravity causes you to fall past an enemy.
If you have house-ruled that the lack of stability caused by being levitated causes even involuntary movement to provoke opportunity attacks, the source of that movement should get the opportunity to make an attack (provided the movement, in fact, would provoke from them).
There's no restriction against making reactions during your turn and letting someone else's opportunity-attack-provoking knockback effect deal a single extra attack at the cost of their reaction isn't a balance problem for a potential use of a 2nd level spell.