Does hexproof prevent a creature from being targeted by its controller's own spells?

Hexproof is defined in CR 702.11b: a permanent with hexproof cannot be the target of spells or abilities your opponents control. Wait — that actually means hexproof only stops opponents from targeting it. The controller of the permanent can target their own hexproof permanent with their own spells and abilities.

So the direct answer flips: No, hexproof does not prevent the controller from targeting their own creature. It only prevents opponents from doing so. This is a very common misconception among newer players.

The relevant rule is CR 702.11b: "Hexproof is an evasion ability. A permanent with hexproof can't be the target of spells or abilities your opponents control." The word 'opponents' is the key — your own spells and abilities are unaffected.

Example: You control a Witchstalker (which has hexproof). Your opponent cannot target it with Murder, but you can target it with your own Giant Growth to give it +3/+3, because your own spells are not restricted by hexproof.

Note: Some cards grant "hexproof from [quality]" (CR 702.11f), and others say a permanent "can't be the target of spells or abilities" with no restriction — that would stop even the controller. Always read the exact wording carefully.