Note that the IRS country code abbreviations do not always correspond with US Postal Service abbreviations.
| Code | Country Name |
| AA | Aruba |
| AC | Antigua & Barbuda |
| AE | United Arab Emirates |
| AF | Afghanistan |
| AG | Algeria |
| AJ | Azerbaijan |
| AL | Albania |
| AM | Armenia |
| AN | Andorra |
| AO | Angola |
| AQ | American Samoa |
| AR | Argentina |
| AS | Australia |
| AT | Ashmore and Cartier Islands |
| AU | Austria |
| AV | Anguilla |
| AX | Akrotiri |
| AY | Antarctica (not valid on Form 2555) |
| BA | Bahrain |
| BB | Barbados |
| BC | Botswana |
| BD | Bermuda |
| BE | Belgium |
| BF | Bahamas |
| BG | Bangladesh |
| BH | Belize |
| BK | Bosnia & Herzegovina |
| BL | Bolivia |
| BM | Burma |
| BN | Benin |
| BO | Belarus |
| BP | Solomon Islands |
| BQ | Navassa Island |
| BR | Brazil |
| BT | Bhutan |
| BU | Bulgaria |
| BV | Bouvet Island |
| BX | Brunei |
| BY | Burundi |
| CA | Canada |
| CB | Cambodia |
| CD | Chad |
| CE | Sri Lanka |
| CF | Congo (Brazzaville) |
| CG | Congo (Kinshasa) |
| CH | China |
| CI | Chile |
| CJ | Cayman Islands |
| CK | Cocos (Keeling) Islands |
| CM | Cameroon |
| CN | Comoros |
| CO | Colombia |
| CQ | Northern Mariana Islands |
| CR | Coral Sea Islands |
| CS | Costa Rica |
| CT | Central African Republic |
| CU | Cuba |
| CV | Cape Verde |
| CW | Cook Islands |
| CY | Cyprus |
| DA | Denmark |
| DJ | Djibouti |
| DO | Dominica |
| DQ | Jarvis Island |
| DR | Dominican Republic |
| DX | Dhekelia |
| EC | Ecuador |
| EG | Egypt |
| EI | Ireland |
| EK | Equatorial Guinea |
| EN | Estonia |
| ER | Eritrea |
| ES | El Salvador |
| ET | Ethiopia |
| EZ | Czech Republic |
| FI | Finland |
| FJ | Fiji |
| FK | Falkland Islands (Islas Malvinas) |
| FM | Federated States of Micronesia |
| FO | Faroe Islands |
| FP | French Polynesia |
| FQ | Baker Island |
| FR | France |
| FS | French Southern & Antarctic Lands |
| GA | The Gambia |
| GB | Gabon |
| GG | Georgia |
| GH | Ghana |
| GI | Gibraltar |
| GJ | Grenada |
| GK | Guernsey |
| GL | Greenland |
| GM | Germany |
| GQ | Guam |
| GR | Greece |
| GT | Guatemala |
| GV | Guinea |
| GY | Guyana |
| HA | Haiti |
| HK | Hong Kong |
| HM | Heard Island / McDonald Islands |
| HO | Honduras |
| HQ | Howland Island |
| HR | Croatia |
| HU | Hungary |
| IC | Iceland |
| ID | Indonesia |
| IM | Isle of Man |
| IN | India |
| IO | British Indian Ocean Territory |
| IP | Clipperton Island |
| IR | Iran |
| IS | Israel |
| IT | Italy |
| IV | Cote d'Ivoire (Ivory Coast) |
| IZ | Iraq |
| JA | Japan |
| JE | Jersey |
| JM | Jamaica |
| JN | Jan Mayen |
| JO | Jordan |
| JQ | Johnston Atoll |
| KE | Kenya |
| KG | Kyrgyzstan |
| KN | Korea, North |
| KQ | Kingman Reef |
| KR | Kiribati |
| KS | Korea, South |
| KT | Christmas Island |
| KU | Kuwait |
| Code | Country Name |
| KV | Kosovo |
| KZ | Kazakhstan |
| LA | Laos |
| LE | Lebanon |
| LG | Latvia |
| LH | Lithuania |
| LI | Liberia |
| LO | Slovakia |
| LQ | Palmyra Atoll |
| LS | Liechtenstein |
| LT | Lesotho |
| LU | Luxembourg |
| LY | Libya |
| MA | Madagascar |
| MC | Macau |
| MD | Moldova |
| MG | Mongolia |
| MH | Montserrat |
| MI | Malawi |
| MJ | Montenegro |
| MK | Macedonia |
| ML | Mali |
| MN | Monaco |
| MO | Morocco |
| MP | Mauritius |
| MQ | Midway Islands |
| MR | Mauritania |
| MT | Malta |
| MU | Oman |
| MV | Maldives |
| MX | Mexico |
| MY | Malaysia |
| MZ | Mozambique |
| NC | New Caledonia |
| NE | Niue |
| NF | Norfolk Island |
| NG | Niger |
| NH | Vanuatu |
| NI | Nigeria |
| NL | Netherlands |
| NN | Sint Maarten |
| NO | Norway |
| NP | Nepal |
| NR | Nauru |
| NS | Suriname |
| NU | Nicaragua |
| NZ | New Zealand |
| OC | Other Country |
| OD | South Sudan |
| PA | Paraguay |
| PC | Pitcairn Islands |
| PE | Peru |
| PF | Paracel Islands |
| PG | Spratly Islands |
| PK | Pakistan |
| PL | Poland |
| PM | Panama |
| PO | Portugal |
| PP | Papua-New Guinea |
| PS | Palau |
| PU | Guinea-Bissau |
| QA | Qatar |
| RI | Serbia |
| RM | Marshall Islands |
| RN | Saint Martin |
| RO | Romania |
| RP | Philippines |
| RQ | Puerto Rico |
| RS | Russia |
| RW | Rwanda |
| SA | Saudi Arabia |
| SB | St. Pierre and Miquelon |
| SC | St. Kitts and Nevis |
| SE | Seychelles |
| SF | South Africa |
| SG | Senegal |
| SH | St. Helena |
| SI | Slovenia |
| SL | Sierra Leone |
| SM | San Marino |
| SN | Singapore |
| SO | Somalia |
| SP | Spain |
| ST | St. Lucia Island |
| SU | Sudan |
| SV | Svalbard |
| SW | Sweden |
| SX | So. Georgia & So. Sandwich Islands |
| SY | Syria |
| SZ | Switzerland |
| TB | Saint Barthelemy |
| TD | Trinidad and Tobago |
| TH | Thailand |
| TI | Tajikistan |
| TK | Turks and Caicos Islands |
| TL | Tokelau |
| TN | Tonga |
| TO | Togo |
| TP | Sao Tome and Principe |
| TS | Tunisia |
| TT | East Timor (Timor-Leste) |
| TU | Turkey |
| TV | Tuvalu |
| TW | Taiwan |
| TX | Turkmenistan |
| TZ | Tanzania |
| UC | Curacao |
| UG | Uganda |
| UK | United Kingdom |
| UP | Ukraine |
| UV | Burkina Faso |
| UY | Uruguay |
| UZ | Uzbekistan |
| VC | St. Vincent and the Grenadines |
| VE | Venezuela |
| VI | British Virgin Islands |
| VM | Vietnam |
| VQ | Virgin Islands |
| VT | Holy See (Vatican) |
| WA | Namibia |
| WF | Wallis and Futuna |
| WI | Western Sahara |
| WQ | Wake Island |
| WS | Samoa |
| WZ | Swaziland |
| YM | Yemen (Aden) |
| ZA | Zambia |
| ZI | Zimbabwe |
| XX | For ITIN Processing |