Can you counterspell a counterspell?

Yes, you can entirely Counterspell a Counterspell!

Because Counterspell has a Somatic component, it fulfills its own trigger condition: seeing a creature within 60 feet "casting a spell with Verbal, Somatic, or Material components" D&D 5e SRD 5.2 — Spe....

However, the 2024 rules completely change the tactics for how this plays out due to the new limit on spellcasting: "On a turn, you can expend only one spell slot to cast a spell" D&D 5e SRD 5.2 — Spe....

Here is how a Counterspell chain works in the new rules:

• Protecting your Cantrips: If you cast a cantrip on your turn and an enemy tries to Counterspell it, you can use your Reaction to Counterspell them (because a cantrip didn't use up your one spell slot for the turn).
• Protecting your Leveled Spells: If you cast a leveled spell on your turn (like Fireball) and an enemy tries to Counterspell it, you cannot Counterspell their Counterspell, as you have already committed your one spell slot for the turn D&D 5e SRD 5.2 — Spe....
• The "Wingman" Counterspell: An ally can use their Reaction to Counterspell the enemy's Counterspell on your turn, provided that ally hasn't somehow already expended a spell slot on this exact turn.

A quick bonus tip for the 2024 rules: Counterspell is no longer an automatic shutdown or a spellcasting ability check. The interrupted caster now makes a Constitution saving throw. If they fail, the spell drops, but they actually keep their spell slot! D&D 5e SRD 5.2 — Spe...

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