Is it spelled grey or gray?

It can be spelled both grey and gray, both are correct spellings of same color between black and white, choice depends on regional English dialect. Gray with a is American English spelling, used in United States and preferred in American dictionaries, official US documents, and American companies like Crayola in US market. Grey with e is British English spelling, used in United Kingdom, Commonwealth countries including India, Australia, Canada, and Europe, and is taught in British English schools. Both spellings are accepted worldwide and mean same color, pronunciation is identical. In everyday writing, you should use spelling that matches your audience and location, if you are in US, use gray, if you are in UK or India where British English is standard, use grey. In international contexts, gray is more common due to American English dominance, but grey is historically more common in British literature. Google data shows gray more frequent in American books, grey more frequent in British books. For proper names, spelling is fixed, for example Earl Grey tea uses grey, and someone named Gray uses gray. So neither spelling is wrong, both are correct, but consistency matters, pick one and use it consistently in your document. If writing for global audience, gray is slightly more widely recognized due to US influence, but grey is equally correct.