Is it permissible to say "Jazakallahu Khairan" (May Allah reward you with goodness) to a non-Muslim if they do a favor?
If a Muslim says to his Muslim brother, who has done him a favor, "May Allah reward you with good (Jazakallahu khairan)," he has fully praised him and exerted his utmost effort in rewarding him, seeking for him a great reward from Allah. This supplication is specific to a Muslim. As for a non-Muslim who performs a good deed, one should supplicate for them with an increase in wealth, children, health, and well-being.
Summarized from the full answer at Ftawy · reviewed Sep 2, 2026
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