How do you say Cinco de Mayo in Gaelic?

There isn't a direct translation of "Cinco de Mayo" in Gaelic (either Irish or Scottish Gaelic) because it's a specific Spanish phrase. You would have to translate the meaning, which is "Fifth of May".

To do that, you'd say something like:

* Irish: An cúigiú lá de Mhí na Bealtaine (This is a more literal translation)

* Scottish Gaelic: An còigeamh latha den Chèitean

These translate to "The fifth day of May". There's no cultural equivalent of Cinco de Mayo in Gaelic-speaking regions to warrant a single, concise phrase.