3A

3A, 3-A or III-A may refer to:


 * 3A (Band), a German pop band
 * Long March 3A, a Chinese rocket
 * Northern Nevada 3A Region, a part of the Nevada Interscholastic Athletics Association governing the northern half of Nevada for high school athletics
 * Route 3A (disambiguation)
 * Stalag III-A, a German prisoner of war camp
 * Zeolite 3A, a potassium-type molecular sieve
 * Google Pixel 3a, a mid-range smartphone manufactured by Google