The answer to this question is that it depends. You are allowed to naturalize if you have had a permanent green card for three years or more. This means if you married a United States citizen and got your green card, the initial green card is a conditional one. The conditions must be removed after two years via the I-751 form, which is a petition to remove conditions. Once approved, USCIS (United States Customs and Immigration Services) will then issue a permanent green card.