Wondering what to wear? Think ~Mediterranean Summer Garden Party~ which I consider to be relaxed, colorful, feminine, and playful.
Please wear colorful cocktail attire :)
How about for the men? Think ~Summer Suit~ tan, blue, or grey. Linen is great for Greece. Most Greek men wear slacks and a button down, but some also wear a suit jacket.
As a whole, the Greeks are a bit more formal in their wedding guest attire, for both men and women.