Legal age requirements for playing blackjack vary widely by jurisdiction, typically ranging from 18 to 21 years old. In the U.S., most states set the minimum age at 21, while some allow players as young as 18, particularly in tribal casinos. Similarly, other countries have different legal gambling ages, with many European nations setting it at 18. These variations depend on local laws and cultural attitudes toward gambling, emphasizing the need to understand specific regulations in each area.