| Rank | Country | Median age |
205 | Afghanistan | total: 18.2 years male: 18.2 years female: 18.2 years (2011 est.) |
| Akrotiri | void |
92 | Albania | total: 30.4 years male: 29.2 years female: 31.6 years (2011 est.) |
119 | Algeria | total: 27.6 years male: 27.4 years female: 27.8 years (2011 est.) |
151 | American Samoa | total: 23.7 years male: 23.6 years female: 23.9 years (2011 est.) |
28 | Andorra | total: 40.5 years male: 40.8 years female: 40.2 years (2011 est.) |
207 | Angola | total: 18.1 years male: 18.1 years female: 18.1 years (2011 est.) |
73 | Anguilla | total: 33.3 years male: 31.9 years female: 34.7 years (2011 est.) |
| Antarctica | void |
94 | Antigua and Barbuda | total: 30.3 years male: 28.7 years female: 31.7 years (2011 est.) |
| Arctic Ocean | void |
91 | Argentina | total: 30.5 years male: 29.5 years female: 31.6 years (2011 est.) |
81 | Armenia | total: 32.2 years male: 29.5 years female: 35 years (2011 est.) |
53 | Aruba | total: 38.2 years male: 36.4 years female: 40 years (2011 est.) |
| Ashmore and Cartier Islands | void |
| Atlantic Ocean | void |
55 | Australia | total: 37.7 years male: 37 years female: 38.4 years (2011 est.) |
6 | Austria | total: 43 years male: 41.9 years female: 44 years (2011 est.) |