diff --git a/README.md b/README.md
index f43f43e..ae149c2 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,10 @@ Report issues for this extension in the [ocds-extensions repository](https://git
 
 ## Changelog
 
+### 2023-06-07
+
+* Add `country.csv` codelist for `nationality` field.
+
 ### 2023-02-27
 
 * Add fields:
diff --git a/codelists/country.csv b/codelists/country.csv
new file mode 100644
index 0000000..67670fc
--- /dev/null
+++ b/codelists/country.csv
@@ -0,0 +1,251 @@
+Code,Title
+AD,Andorra
+AE,United Arab Emirates
+AF,Afghanistan
+AG,Antigua and Barbuda
+AI,Anguilla
+AL,Albania
+AM,Armenia
+AO,Angola
+AQ,Antarctica
+AR,Argentina
+AS,American Samoa
+AT,Austria
+AU,Australia
+AW,Aruba
+AX,Åland Islands
+AZ,Azerbaijan
+BA,Bosnia and Herzegovina
+BB,Barbados
+BD,Bangladesh
+BE,Belgium
+BF,Burkina Faso
+BG,Bulgaria
+BH,Bahrain
+BI,Burundi
+BJ,Benin
+BL,Saint Barthélemy
+BM,Bermuda
+BN,Brunei Darussalam
+BO,Bolivia (Plurinational State of)
+BQ,"Bonaire, Sint Eustatius and Saba"
+BR,Brazil
+BS,Bahamas
+BT,Bhutan
+BV,Bouvet Island
+BW,Botswana
+BY,Belarus
+BZ,Belize
+CA,Canada
+CC,Cocos (Keeling) Islands
+CD,Congo (the Democratic Republic of the)
+CF,Central African Republic
+CG,Congo
+CH,Switzerland
+CI,Côte d'Ivoire
+CK,Cook Islands
+CL,Chile
+CM,Cameroon
+CN,China
+CO,Colombia
+CR,Costa Rica
+CU,Cuba
+CV,Cabo Verde
+CW,Curaçao
+CX,Christmas Island
+CY,Cyprus
+CZ,Czechia
+DE,Germany
+DJ,Djibouti
+DK,Denmark
+DM,Dominica
+DO,Dominican Republic
+DZ,Algeria
+EC,Ecuador
+EE,Estonia
+EG,Egypt
+EH,Western Sahara
+ER,Eritrea
+ES,Spain
+ET,Ethiopia
+FI,Finland
+FJ,Fiji
+FK,Falkland Islands [Malvinas]
+FM,Micronesia (Federated States of)
+FO,Faroe Islands
+FR,France
+GA,Gabon
+GB,United Kingdom of Great Britain and Northern Ireland
+GD,Grenada
+GE,Georgia
+GF,French Guiana
+GG,Guernsey
+GH,Ghana
+GI,Gibraltar
+GL,Greenland
+GM,Gambia
+GN,Guinea
+GP,Guadeloupe
+GQ,Equatorial Guinea
+GR,Greece
+GS,South Georgia and the South Sandwich Islands
+GT,Guatemala
+GU,Guam
+GW,Guinea-Bissau
+GY,Guyana
+HK,Hong Kong
+HM,Heard Island and McDonald Islands
+HN,Honduras
+HR,Croatia
+HT,Haiti
+HU,Hungary
+ID,Indonesia
+IE,Ireland
+IL,Israel
+IM,Isle of Man
+IN,India
+IO,British Indian Ocean Territory
+IQ,Iraq
+IR,Iran (Islamic Republic of)
+IS,Iceland
+IT,Italy
+JE,Jersey
+JM,Jamaica
+JO,Jordan
+JP,Japan
+KE,Kenya
+KG,Kyrgyzstan
+KH,Cambodia
+KI,Kiribati
+KM,Comoros
+KN,Saint Kitts and Nevis
+KP,Korea (the Democratic People's Republic of)
+KR,Korea (the Republic of)
+KW,Kuwait
+KY,Cayman Islands
+KZ,Kazakhstan
+LA,Lao People's Democratic Republic
+LB,Lebanon
+LC,Saint Lucia
+LI,Liechtenstein
+LK,Sri Lanka
+LR,Liberia
+LS,Lesotho
+LT,Lithuania
+LU,Luxembourg
+LV,Latvia
+LY,Libya
+MA,Morocco
+MC,Monaco
+MD,Moldova (the Republic of)
+ME,Montenegro
+MF,Saint Martin (French part)
+MG,Madagascar
+MH,Marshall Islands
+MK,North Macedonia
+ML,Mali
+MM,Myanmar
+MN,Mongolia
+MO,Macao
+MP,Northern Mariana Islands
+MQ,Martinique
+MR,Mauritania
+MS,Montserrat
+MT,Malta
+MU,Mauritius
+MV,Maldives
+MW,Malawi
+MX,Mexico
+MY,Malaysia
+MZ,Mozambique
+NA,Namibia
+NC,New Caledonia
+NE,Niger
+NF,Norfolk Island
+NG,Nigeria
+NI,Nicaragua
+NL,Netherlands
+NO,Norway
+NP,Nepal
+NR,Nauru
+NU,Niue
+NZ,New Zealand
+OM,Oman
+PA,Panama
+PE,Peru
+PF,French Polynesia
+PG,Papua New Guinea
+PH,Philippines
+PK,Pakistan
+PL,Poland
+PM,Saint Pierre and Miquelon
+PN,Pitcairn
+PR,Puerto Rico
+PS,"Palestine, State of"
+PT,Portugal
+PW,Palau
+PY,Paraguay
+QA,Qatar
+RE,Réunion
+RO,Romania
+RS,Serbia
+RU,Russian Federation
+RW,Rwanda
+SA,Saudi Arabia
+SB,Solomon Islands
+SC,Seychelles
+SD,Sudan
+SE,Sweden
+SG,Singapore
+SH,"Saint Helena, Ascension and Tristan da Cunha"
+SI,Slovenia
+SJ,Svalbard and Jan Mayen
+SK,Slovakia
+SL,Sierra Leone
+SM,San Marino
+SN,Senegal
+SO,Somalia
+SR,Suriname
+SS,South Sudan
+ST,Sao Tome and Principe
+SV,El Salvador
+SX,Sint Maarten (Dutch part)
+SY,Syrian Arab Republic
+SZ,Eswatini
+TC,Turks and Caicos Islands
+TD,Chad
+TF,French Southern Territories
+TG,Togo
+TH,Thailand
+TJ,Tajikistan
+TK,Tokelau
+TL,Timor-Leste
+TM,Turkmenistan
+TN,Tunisia
+TO,Tonga
+TR,Turkey
+TT,Trinidad and Tobago
+TV,Tuvalu
+TW,Taiwan (Province of China)
+TZ,"Tanzania, the United Republic of"
+UA,Ukraine
+UG,Uganda
+UM,United States Minor Outlying Islands
+US,United States of America
+UY,Uruguay
+UZ,Uzbekistan
+VA,Holy See
+VC,Saint Vincent and the Grenadines
+VE,Venezuela (Bolivarian Republic of)
+VG,Virgin Islands (British)
+VI,Virgin Islands (U.S.)
+VN,Viet Nam
+VU,Vanuatu
+WF,Wallis and Futuna
+WS,Samoa
+XK,Kosovo
+YE,Yemen
+YT,Mayotte
+ZA,South Africa
+ZM,Zambia
+ZW,Zimbabwe
diff --git a/release-schema.json b/release-schema.json
index 07e52f7..fa6fedc 100644
--- a/release-schema.json
+++ b/release-schema.json
@@ -56,12 +56,266 @@
         },
         "nationality": {
           "title": "Nationality",
-          "description": "The nationality of the person, as a two-letter, uppercase ISO 3166-1 alpha-2 country code.",
+          "description": "The nationality of the person, from the closed country codelist.",
           "type": [
             "string",
             "null"
           ],
-          "minLength": 1
+          "codelist": "country.csv",
+          "openCodelist": false,
+          "enum": [
+            "AD",
+            "AE",
+            "AF",
+            "AG",
+            "AI",
+            "AL",
+            "AM",
+            "AO",
+            "AQ",
+            "AR",
+            "AS",
+            "AT",
+            "AU",
+            "AW",
+            "AX",
+            "AZ",
+            "BA",
+            "BB",
+            "BD",
+            "BE",
+            "BF",
+            "BG",
+            "BH",
+            "BI",
+            "BJ",
+            "BL",
+            "BM",
+            "BN",
+            "BO",
+            "BQ",
+            "BR",
+            "BS",
+            "BT",
+            "BV",
+            "BW",
+            "BY",
+            "BZ",
+            "CA",
+            "CC",
+            "CD",
+            "CF",
+            "CG",
+            "CH",
+            "CI",
+            "CK",
+            "CL",
+            "CM",
+            "CN",
+            "CO",
+            "CR",
+            "CU",
+            "CV",
+            "CW",
+            "CX",
+            "CY",
+            "CZ",
+            "DE",
+            "DJ",
+            "DK",
+            "DM",
+            "DO",
+            "DZ",
+            "EC",
+            "EE",
+            "EG",
+            "EH",
+            "ER",
+            "ES",
+            "ET",
+            "FI",
+            "FJ",
+            "FK",
+            "FM",
+            "FO",
+            "FR",
+            "GA",
+            "GB",
+            "GD",
+            "GE",
+            "GF",
+            "GG",
+            "GH",
+            "GI",
+            "GL",
+            "GM",
+            "GN",
+            "GP",
+            "GQ",
+            "GR",
+            "GS",
+            "GT",
+            "GU",
+            "GW",
+            "GY",
+            "HK",
+            "HM",
+            "HN",
+            "HR",
+            "HT",
+            "HU",
+            "ID",
+            "IE",
+            "IL",
+            "IM",
+            "IN",
+            "IO",
+            "IQ",
+            "IR",
+            "IS",
+            "IT",
+            "JE",
+            "JM",
+            "JO",
+            "JP",
+            "KE",
+            "KG",
+            "KH",
+            "KI",
+            "KM",
+            "KN",
+            "KP",
+            "KR",
+            "KW",
+            "KY",
+            "KZ",
+            "LA",
+            "LB",
+            "LC",
+            "LI",
+            "LK",
+            "LR",
+            "LS",
+            "LT",
+            "LU",
+            "LV",
+            "LY",
+            "MA",
+            "MC",
+            "MD",
+            "ME",
+            "MF",
+            "MG",
+            "MH",
+            "MK",
+            "ML",
+            "MM",
+            "MN",
+            "MO",
+            "MP",
+            "MQ",
+            "MR",
+            "MS",
+            "MT",
+            "MU",
+            "MV",
+            "MW",
+            "MX",
+            "MY",
+            "MZ",
+            "NA",
+            "NC",
+            "NE",
+            "NF",
+            "NG",
+            "NI",
+            "NL",
+            "NO",
+            "NP",
+            "NR",
+            "NU",
+            "NZ",
+            "OM",
+            "PA",
+            "PE",
+            "PF",
+            "PG",
+            "PH",
+            "PK",
+            "PL",
+            "PM",
+            "PN",
+            "PR",
+            "PS",
+            "PT",
+            "PW",
+            "PY",
+            "QA",
+            "RE",
+            "RO",
+            "RS",
+            "RU",
+            "RW",
+            "SA",
+            "SB",
+            "SC",
+            "SD",
+            "SE",
+            "SG",
+            "SH",
+            "SI",
+            "SJ",
+            "SK",
+            "SL",
+            "SM",
+            "SN",
+            "SO",
+            "SR",
+            "SS",
+            "ST",
+            "SV",
+            "SX",
+            "SY",
+            "SZ",
+            "TC",
+            "TD",
+            "TF",
+            "TG",
+            "TH",
+            "TJ",
+            "TK",
+            "TL",
+            "TM",
+            "TN",
+            "TO",
+            "TR",
+            "TT",
+            "TV",
+            "TW",
+            "TZ",
+            "UA",
+            "UG",
+            "UM",
+            "US",
+            "UY",
+            "UZ",
+            "VA",
+            "VC",
+            "VE",
+            "VG",
+            "VI",
+            "VN",
+            "VU",
+            "WF",
+            "WS",
+            "XK",
+            "YE",
+            "YT",
+            "ZA",
+            "ZM",
+            "ZW",
+            null
+          ]
         },
         "address": {
           "title": "Address",