http://www.pcgamer.com/european-game-rating-body-agrees-with-esrb-loot-boxes-arent-gambling/

The Entertainment Software Rating Board, the agency that doles out age ratings to videogames in North America, declared a couple of days ago that loot boxes, despite their inherent randomness, do not constitute a form of gambling. The reason, simply put, is that while you don't know what you're going to get out of them, you know you're going to get something—unlike a lottery ticket, say, where the great likelihood is that your money is just going up in smoke. 

Not everyone agrees with the ESRB's decision, as can you tell from the comments on that post. But two particular groups do: PEGI—Pan European Game Information, which rates games in Europe—and Ukie, UK's game industry trade body, both said that they agree with the ESRB's position.