How do you spell Harley in Gaelic?

There isn't a direct, single Gaelic translation for the name "Harley." Gaelic (both Scottish Gaelic and Irish Gaelic) doesn't translate names word-for-word like some languages might. To get a Gaelic-sounding name, you'd need to find a name with a similar meaning or sound.

To find an equivalent, you'd need to know what the meaning of Harley is to you – is it the sound, the meaning (if it has one you like), or a feeling it evokes? Then you could research Gaelic names with similar qualities. You might find something that sounds close phonetically, or which shares a similar meaning (like "hare" in relation to the name's possible connection to a "hare-field").