Convoke is a keyword ability that lets you tap creatures you control to help pay the mana cost of a spell you're casting. However, tapping a creature for convoke is still subject to the same restrictions as tapping a creature for any other purpose.
Under CR 302.6, a creature is affected by summoning sickness if it has not been under its controller's control since the beginning of their most recent turn. Such a creature cannot be tapped to activate an ability with the tap symbol (⟨T⟩) in the cost. CR 702.46c specifically states that tapping a creature for convoke follows the same rules as tapping a creature to pay a cost with the tap symbol — meaning summoning sickness applies.
In other words, if you want to tap a creature to pay for convoke, that creature must have been under your control continuously since the start of your current turn (or have haste, per CR 702.10). The fact that you're paying for a spell rather than an activated ability makes no difference here.
Example: You play a Llanowar Elves on your turn and then try to cast a convoke spell, tapping the Elves to reduce its cost. This is not allowed — the Elves just entered the battlefield this turn and have summoning sickness, so they cannot be tapped for convoke.
Note that creatures can still be untapped to pay convoke costs (some convoke cards or effects care about this), but the standard tap-for-convoke action is blocked by summoning sickness just as any other tap cost would be.
Unofficial fan resource — not affiliated with or endorsed by Wizards of the Coast. Answers are AI-generated estimates grounded in the Comprehensive Rules and are not a substitute for an official judge. Verify anything match-critical.