Is it ever really okay to wear white at a wedding when you're not the bride? Yes, but only if the bride requests/asks you to. Such as she's have a white themed wedding and asks her guests to wear white. This is the ONLY time it is acceptable for guests to wear white. I repeat this is the only time a guest, especially a woman, should wear white to a wedding.
If you are a female guest attending the wedding, no matter how cute the little white dress may be, do NOT wear it to the wedding! This happens more often than people think, especially with summer weddings. If the bride decides to wear the traditional white wedding dress, do not wear an all white dress! It’s her big day and she want’s to stand out!