Become a citizen through your U.S. military service

To qualify for citizenship (naturalization), you must:

• Be at least18 years old;
• Have served for at least a year (or periods totaling at least 1 year);
• Have served and ended service honorably;
• Be a lawful permanent resident (green card holder) when you have your naturalization interview;
• Lived and stayed in the U.S. for long enough; 
• Show you can read, write and speak English (unless you qualify for a waiver or exception);
• Show knowledge of U.S. history and government, unless excepted;
• Prove good moral character (that you are a good person and avoided certain problems) for at least five years before filing your N-400 through the day you naturalize; and
• Be willing to take the oath. 

This is a link to the section of the USCIS website that has immigration information and links to resources that are for members of the military and their families.