Date | Country | Change |
| 1956 |  Israel | Titular Episcopal See of Ptolemais in Phœnicia (Maronite Rite) was restored |
| 1956 |  Syria | Titular Archiepiscopal See of Cyrrhus (Maronite Rite) was suppressed |
| 1956 |  Turkiye | Titular Archiepiscopal See of Chalcedon (Armenian Rite) was suppressed |
| 1956 | Turkiye | Titular Archiepiscopal See of Seleucia pieria was renamed as Titular Archiepiscopal See of Seleucia Pieria |
| 1956 | | Titular Episcopal See of Lorea was suppressed |
| 1956 | | Titular Episcopal See of Tingis was suppressed |
| 1956.01.01 |  Spain | Diocese of Huesca lost territory to Diocese of Jaca |
| 1956.01.22 |  Ecuador | Diocese of Guayaquil was promoted as Metropolitan Archdiocese of Guayaquil (with suffragan sees Portoviejo, El Oro and Los Ríos) |
| 1956.01.28 |  Bermuda | Apostolic Prefecture of Bermuda Islands was promoted as Apostolic Vicariate of Bermuda Islands |
| 1956.02.01 |  Brazil | Diocese of Governador Valadares was established (from Metropolitan Archdiocese of Diamantina, Diocese of Araçuaí and Diocese of Caratinga and became suffragan of Mariana) |
| 1956.02.01 | Brazil | Diocese of Londrina was established (from Diocese of Jacarezinho and became suffragan of Curitiba) |
| 1956.02.01 | Brazil | Diocese of Maringá was established (from Diocese of Jacarezinho and became suffragan of Curitiba) |
| 1956.02.20 |  Burkina Faso | Diocese of Koupéla was established (from Metropolitan Archdiocese of Ouagadougou) |
| 1956.02.20 |  Grenada | Diocese of Saint George’s in Grenada was established (from Metropolitan Archdiocese of Port of Spain and became suffragan of Port of Spain) |
| 1956.02.20 |  India | Diocese of Meerut was established (from Metropolitan Archdiocese of Agra and became suffragan of Agra) |
| 1956.02.20 |  Kenya | Apostolic Prefecture of Kitui was established (from Metropolitan Archdiocese of Nairobi and Diocese of Meru) |
| 1956.02.20 |  Saint Lucia | Diocese of Castries was established (from Metropolitan Archdiocese of Port of Spain and without ecclesiastical province) |
| 1956.02.29 |  Belize | Apostolic Vicariate of Belize was promoted as Diocese of Belize |
| 1956.02.29 |  French Guiana | Apostolic Vicariate of French Guiana was promoted as Diocese of Cayenne (without ecclesiastical province) |
| 1956.02.29 |  Guyana | Apostolic Vicariate of British Guiana was promoted as Diocese of Georgetown (became suffragan of Port of Spain) |
| 1956.02.29 |  Italy | Diocese of Veroli was renamed as Diocese of Veroli–Frosinone |
| 1956.02.29 |  Jamaica | Apostolic Vicariate of Jamaica was promoted as Diocese of Kingston (without ecclesiastical province) |
| 1956.03.02 |  Peru | Apostolic Vicariate of Pucallpa was established (from Apostolic Vicariate of Ucayali) |
| 1956.03.02 | Peru | Apostolic Vicariate of Requena was established (from Apostolic Vicariate of Ucayali) |
| 1956.03.02 | Peru | Apostolic Vicariate of Ucayali was renamed as Apostolic Vicariate of San Ramón (lost territory to establish Apostolic Vicariate of Pucallpa and Apostolic Vicariate of Requena) |
| 1956.03.26 | Brazil | Territorial Prelature of Bananal was renamed as Territorial Prelature of Cristalândia (gained territory from Diocese of Porto Nacional, gained territory from the suppressed Territorial Prelature of São José de Alto Tocantins, lost territory to Diocese of Goiás and became suffragan of Goiânia) |
| 1956.03.26 | Brazil | Territorial Prelature of Formosa was established (from Metropolitan Archdiocese of Goiás, from the suppressed Territorial Prelature of São José de Alto Tocantins and became suffragan of Goiânia) |
| 1956.03.26 | Brazil | Metropolitan Archdiocese of Goiás was demoted as Diocese of Goiás (gained territory from Territorial Prelature of Bananal, lost territory to establish Metropolitan Archdiocese of Goiânia, Diocese of Uruaçu and Territorial Prelature of Formosa and became suffragan of Goiânia) |
| 1956.03.26 | Brazil | Metropolitan Archdiocese of Goiânia was established (from Metropolitan Archdiocese of Goiás and with suffragan sees Goiás, Jataí, Porto Nacional, Uruaçu, Cristalândia, Formosa and Tocantinópolis) |
| 1956.03.26 | Brazil | Territorial Prelature of Jataí was promoted as Diocese of Jataí (became suffragan of Goiânia) |
| 1956.03.26 | Brazil | Diocese of Porto Nacional lost territory to Territorial Prelature of Cristalândia |
| 1956.03.26 | Brazil | Territorial Prelature of São José de Alto Tocantins was suppressed (to Territorial Prelature of Cristalândia and to establish Diocese of Uruaçu and Territorial Prelature of Formosa) |
| 1956.03.26 | Brazil | Diocese of Uruaçu was established (from Metropolitan Archdiocese of Goiás, from the suppressed Territorial Prelature of São José de Alto Tocantins and became suffragan of Goiânia) |
| 1956.04.07 |  Colombia | Apostolic Prefecture of Vichada was established (from Apostolic Vicariate of Villavicencio) |
| 1956.04.23 |  Congo-Kinshasa | Apostolic Vicariate of Kindu was established (from Apostolic Vicariate of Kongolo and Apostolic Vicariate of Stanleyville) |
| 1956.04.23 |  Ghana | Diocese of Navrongo was restored (from Diocese of Keta and Diocese of Tamale and became suffragan of Cape Coast) |
| 1956.04.23 |  Indonesia | Apostolic Prefecture of Sintang was promoted as Apostolic Vicariate of Sintang |
| 1956.04.24 | Italy | Diocese of Ortona lost territory to Metropolitan Archdiocese of Lanciano |
| 1956.04.29 |  Malawi | Apostolic Vicariate of Dedza was established (from Apostolic Vicariate of Likuni and Apostolic Vicariate of Zomba) |
| 1956.05.29 | Colombia | Diocese of Cúcuta was established (from Diocese of Nueva Pamplona, from the suppressed Apostolic Prefecture of Labateca and became suffragan of Nueva Pamplona) |
| 1956.05.29 | Colombia | Diocese of Girardot was established (from Metropolitan Archdiocese of Bogotá and became suffragan of Bogotá) |
| 1956.05.29 | Colombia | Apostolic Prefecture of Labateca was suppressed (to Metropolitan Archdiocese of Nueva Pamplona and Apostolic Prefecture of Arauca and to establish Diocese of Cúcuta) |
| 1956.05.29 | Colombia | Diocese of Nueva Pamplona was promoted as Metropolitan Archdiocese of Nueva Pamplona (with suffragan sees Bucaramanga, Cúcuta, Socorro y San Gil and Bertrania en el Catatumbo, gained territory from the suppressed Apostolic Prefecture of Labateca and lost territory to establish Diocese of Cúcuta) |
| 1956.06.14 |  Bangladesh | Diocese of Jessore was renamed as Diocese of Khulna |
| 1956.06.25 |  Cote d’Ivoire | Diocese of Gagnoa was established (from Diocese of Daloa and became suffragan of Abidjan) |
| 1956.07.02 | Brazil | Diocese of Afogados da Ingazeira was established (from Diocese of Pesqueira and became suffragan of Olinda e Recife) |
| 1956.07.02 |  USA | Diocese of Atlanta was established (from Diocese of Savannah–Atlanta and became suffragan of Baltimore) |
| 1956.07.02 | USA | Diocese of Jefferson City was established (from Metropolitan Archdiocese of Saint Louis and Diocese of Kansas City, from the suppressed Diocese of Saint Joseph and became suffragan of Saint Louis) |
| 1956.07.02 | USA | Diocese of Kansas City was renamed as Diocese of Kansas City–Saint Joseph (gained territory from the suppressed Diocese of Saint Joseph and lost territory to establish Diocese of Jefferson City and Diocese of Springfield–Cape Girardeau) |
| 1956.07.02 | USA | Diocese of Saint Joseph was suppressed (to Diocese of Kansas City–Saint Joseph and to establish Diocese of Jefferson City and Diocese of Springfield–Cape Girardeau) |
| 1956.07.02 | USA | Diocese of Savannah–Atlanta was renamed as Diocese of Savannah (lost territory to establish Diocese of Atlanta) |
| 1956.07.02 | USA | Diocese of Springfield–Cape Girardeau was established (from Metropolitan Archdiocese of Saint Louis and Diocese of Kansas City, from the suppressed Diocese of Saint Joseph and became suffragan of Saint Louis) |
| 1956.07.18 |  Portugal | Diocese of Portalegre was renamed as Diocese of Portalegre–Castelo Branco |
| 1956.07.20 | USA | Apostolic Exarchate of Stamford (Ukrainian Rite) was established (from Apostolic Exarchate of United States of America) |
| 1956.07.29 | India | Diocese of Kothamangalam (Syro-Malabar Rite) was established (from Metropolitan Archdiocese of Ernakulam and became suffragan of Ernakulam) |
| 1956.08.03 | India | Apostolic Prefecture of Bhagalpur was established (from Diocese of Patna) |
| 1956.08.09 |  Tanzania | Diocese of Maswa was renamed as Diocese of Shinyanga |
| 1956.08.11 | Spain | Diocese of Pamplona was promoted as Metropolitan Archdiocese of Pamplona (with suffragan sees Calahorra y La Calzada, Jaca, San Sebastián and Tudela and lost territory to Diocese of Calahorra y La Calzada) |
| 1956.09.16 |  Guatemala | Territorial Prelature of Santo Cristo de Esquipulas was established (from Diocese of Zacapa and became suffragan of Guatemala) |
| 1956.09.19 | Spain | Diocese of Astorga lost territory to Diocese of León |
| 1956.11.03 |  Canada | Apostolic Exarchate of Edmonton (Ukrainian Rite) was promoted as Diocese of Edmonton (became suffragan of Winnipeg) |
| 1956.11.03 | Canada | Apostolic Exarchate of Saskatoon (Ukrainian Rite) was promoted as Diocese of Saskatoon (became suffragan of Winnipeg) |
| 1956.11.03 | Canada | Apostolic Exarchate of Toronto (Ukrainian Rite) was promoted as Diocese of Toronto (became suffragan of Winnipeg) |
| 1956.11.03 | Canada | Apostolic Exarchate of Manitoba (Ukrainian Rite) was promoted as Metropolitan Archdiocese of Winnipeg (with suffragan sees Edmonton, Saskatoon and Toronto) |
| 1956.11.11 |  Papua New Guinea | Apostolic Prefecture of Aitape was promoted as Apostolic Vicariate of Aitape |
| 1956.11.11 | Papua New Guinea | Apostolic Prefecture of Samarai was promoted as Apostolic Vicariate of Samarai |
| 1956.11.14 |  Morocco | Apostolic Vicariate of Marruecos was promoted as Archdiocese of Tánger (without ecclesiastical province) |
| 1956.12.10 | USA | Diocese of Gary was established (from Diocese of Fort Wayne and became suffragan of Indianapolis) |
| 1956.12.17 | Peru | Diocese of Chiclayo was established (from Metropolitan Archdiocese of Trujillo and Diocese of Cajamarca and became suffragan of Trujillo) |
| 1956.12.18 | USA | Diocese of Natchez was renamed as Diocese of Natchez–Jackson |
| 1956.12.19 |  Chad | Apostolic Prefecture of Pala was established (from Diocese of Garoua) |
