Date | Country | Change |
| 1926 |  Bulgaria | Titular Metropolitan See of Philippopolis was renamed as Titular Metropolitan See of Philippopolis |
| 1926 | Bulgaria | Apostolic Exarchate of Sofia (Bulgarian Rite) was established (from the suppressed Apostolic Vicariate of Constantinople, Apostolic Vicariate of Macedonia and Apostolic Vicariate of Tracia) |
| 1926 |  Egypt | Titular Metropolitan See of Ptolemais was renamed as Titular Metropolitan See of Ptolemais |
| 1926 |  Greece | Titular Episcopal See of Cassandria was established |
| 1926 | Greece,  North Macedonia | Apostolic Vicariate of Macedonia (Bulgarian Rite) was suppressed (to establish Apostolic Exarchate of Sofia) |
| 1926 | Greece | Titular Episcopal See of Mosynopolis was renamed as Titular Episcopal See of Mosynopolis |
| 1926 | Greece | Titular Metropolitan See of Nicopolis was renamed as Titular Metropolitan See of Nicopolis |
| 1926 | Greece | Titular Metropolitan See of Thebæ was renamed as Titular Metropolitan See of Thebæ |
| 1926 | Greece | Titular Metropolitan See of Traianopolis was renamed as Titular Metropolitan See of Traianopolis |
| 1926 | Greece | Titular Metropolitan See of Traianopolis in Rhodope (Armenian Rite) was restored |
| 1926 |  Iran | Titular Episcopal See of Soltania was suppressed |
| 1926 |  Israel | Titular Episcopal See of Helenopolis was renamed as Titular Episcopal See of Helenopolis |
| 1926 | Israel | Titular Archiepiscopal See of Nazareth (Maronite Rite) was restored |
| 1926 | Israel | Titular Episcopal See of Ptolemais was renamed as Titular Episcopal See of Ptolemais |
| 1926 | Israel | Titular Episcopal See of Ptolemais (Maronite Rite) was renamed as Titular Episcopal See of Ptolemais |
| 1926 | Israel | Titular Episcopal See of Tricomia was suppressed |
| 1926 |  Italy | Titular Episcopal See of Sinis was suppressed |
| 1926 |  Lebanon | Titular Episcopal See of Tripolis was renamed as Titular Episcopal See of Tripolis |
| 1926 |  Libya | Titular Episcopal See of Œa was renamed as Titular Episcopal See of Œa |
| 1926 |  Romania | Titular Archiepiscopal See of Constantia was demoted as Titular Episcopal See of Constantia |
| 1926 |  Serbia | Titular Episcopal See of Belgrado e Semendria was renamed as Titular Episcopal See of Belogradum et Semendria |
| 1926 |  Syria | Titular Episcopal See of Cæsarea Paneas was renamed as Titular Episcopal See of Cæsarea |
| 1926 | Syria | Titular Metropolitan See of Hemesa was demoted as Titular Episcopal See of Hemesa |
| 1926 | Syria | Titular Episcopal See of Hierapolis (Syriac Rite) was renamed as Titular Episcopal See of Hierapolis |
| 1926 | Syria | Titular Metropolitan See of Hierapolis was renamed as Titular Metropolitan See of Hierapolis in Syria |
| 1926 | Syria | Titular Episcopal See of Neocæsarea was renamed as Titular Episcopal See of Neocæsarea |
| 1926 | Syria | Titular Episcopal See of Philippopolis was renamed as Titular Episcopal See of Philippopolis |
| 1926 |  Tunisia | Titular Episcopal See of Trisipa was established |
| 1926 |  Turkiye | Titular Episcopal See of Claudiopolis was renamed as Titular Episcopal See of Claudiopolis |
| 1926 | Turkiye, Bulgaria, Greece | Apostolic Vicariate of Constantinople (Bulgarian Rite) was suppressed (to establish Apostolic Exarchate of Sofia) |
| 1926 | Turkiye | Titular Metropolitan See of Cæsarea was renamed as Titular Metropolitan See of Cæsarea |
| 1926 | Turkiye | Titular Episcopal See of Helenopolis was renamed as Titular Episcopal See of Helenopolis |
| 1926 | Turkiye | Titular Metropolitan See of Hierapolis was renamed as Titular Metropolitan See of Hierapolis |
| 1926 | Turkiye | Titular Episcopal See of Irenopolis was renamed as Titular Episcopal See of Irenopolis |
| 1926 | Turkiye | Titular Episcopal See of Irenopolis was renamed as Titular Episcopal See of Irenopolis |
| 1926 | Turkiye | Titular Episcopal See of Jsaura Nova was renamed as Titular Episcopal See of Isauropolis |
| 1926 | Turkiye | Titular Metropolitan See of Neocæsarea was renamed as Titular Metropolitan See of Neocæsarea |
| 1926 | Turkiye | Titular Episcopal See of Nicopolis was renamed as Titular Episcopal See of Nicopolis |
| 1926 | Turkiye | Titular Episcopal See of Phoba (Syriac Rite) was established |
| 1926 | Turkiye | Titular Episcopal See of Sebaste was renamed as Titular Episcopal See of Sebaste |
| 1926 | Turkiye | Titular Metropolitan See of Sebastea was renamed as Titular Metropolitan See of Sebastea |
| 1926 | Turkiye | Titular Episcopal See of Siniandus was established |
| 1926 | Turkiye | Titular Episcopal See of Stadia was established |
| 1926 | Turkiye | Titular Episcopal See of Tarsus (Maronite Rite) was restored |
| 1926 | Turkiye | Titular Episcopal See of Theodosiopolis was renamed as Titular Episcopal See of Theodosiopolis |
| 1926 | Turkiye | Titular Episcopal See of Theodosiopolis was renamed as Titular Episcopal See of Theodosiopolis |
| 1926 | Turkiye | Titular Episcopal See of Titiupolis was renamed as Titular Episcopal See of Titopolis |
| 1926 | Turkiye, Bulgaria | Apostolic Vicariate of Tracia (Bulgarian Rite) was suppressed (to establish Apostolic Exarchate of Sofia) |
| 1926 | Turkiye | Titular Episcopal See of Traianopolis was renamed as Titular Episcopal See of Traianopolis |
| 1926 | Turkiye | Titular Episcopal See of Verbe was established |
| 1926 |  Ukraine | Titular Archiepiscopal See of Bosporus was established |
| 1926 | | Titular Episcopal See of Ioppe (Syriac Rite) was restored |
| 1926.01.11 |  Ghana | Apostolic Prefecture of Navrongo was established (from Apostolic Vicariate of Ouagadougou) |
| 1926.01.28 |  Congo-Kinshasa | Apostolic Prefecture of Tsuapa was renamed as Apostolic Prefecture of Coquilhatville (gained territory from Apostolic Vicariate of Nouvelle-Anvers) |
| 1926.01.28 | Congo-Kinshasa | Apostolic Vicariate of Nouvelle-Anvers lost territory to Apostolic Prefecture of Coquilhatville |
| 1926.03.10 |  Albania | Archdiocese of Durrës lost territory to Metropolitan Archdiocese of Corfu–Zakynthos–Kefalonia |
| 1926.03.10 | Congo-Kinshasa | Apostolic Prefecture of Bondo was established (from Apostolic Vicariate of Uélé Occidentale) |
| 1926.03.10 | Congo-Kinshasa | Apostolic Vicariate of Uélé Occidentale was renamed as Apostolic Vicariate of Buta (lost territory to establish Apostolic Prefecture of Bondo) |
| 1926.03.10 |  Kenya | Apostolic Prefecture of Meru was established (from Apostolic Vicariate of Kenya) |
| 1926.03.10 | Kenya | Apostolic Vicariate of Kenya was renamed as Apostolic Vicariate of Nyeri (lost territory to establish Apostolic Prefecture of Meru) |
| 1926.03.16 | Turkiye | Apostolic Vicariate of Constantinopole lost territory to Diocese of Skopje |
| 1926.03.18 | Greece | Apostolic Vicariate of Salonica was established (from Apostolic Vicariate of Constantinopole) |
| 1926.03.20 | Italy | Territorial Prelature of Beatissima Vergine Maria del Santissimo Rosario was established (from Diocese of Castellammare di Stabia and Diocese of Nola and became suffragan of Napoli) |
| 1926.04.04 |  Lithuania | Diocese of Kaišiadorys was established (from Metropolitan Archdiocese of Vilnius and became suffragan of Vilnius) |
| 1926.04.04 | Lithuania | Metropolitan Archdiocese of Kaunas was established (from the suppressed Diocese of Žemaitija and with suffragan sees Panevėžys, Telšiai, Vilkaviškis and Klaipėda) |
| 1926.04.04 | Lithuania | Territorial Prelature of Klaipėda was established (from Diocese of Warmia and became suffragan of Kaunas) |
| 1926.04.04 | Lithuania | Diocese of Panevėžys was established (from the suppressed Diocese of Žemaitija and became suffragan of Kaunas) |
| 1926.04.04 | Lithuania | Diocese of Telšiai was established (from the suppressed Diocese of Žemaitija and became suffragan of Kaunas) |
| 1926.04.04 | Lithuania | Diocese of Vilkaviškis was established (from Diocese of Łomża, from the suppressed Diocese of Žemaitija and became suffragan of Kaunas) |
| 1926.04.04 | Lithuania | Diocese of Žemaitija was suppressed (to establish Metropolitan Archdiocese of Kaunas, Diocese of Panevėžys, Diocese of Telšiai and Diocese of Vilkaviškis) |
| 1926.04.11 |  Russia | Apostolic Administration of Leningrad was established (from Metropolitan Archdiocese of Mohilev) |
| 1926.04.16 | Italy | Metropolitan Archdiocese of Udine lost territory to Diocese of Ceneda |
| 1926.05.10 |  Brazil | Diocese of Curitiba was promoted as Metropolitan Archdiocese of Curitiba (with suffragan sees Jacarezinho, Ponta Grossa and Foz do Iguaçu and lost territory to establish Diocese of Jacarezinho, Diocese of Ponta Grossa and Territorial Prelature of Foz do Iguaçu) |
| 1926.05.10 | Brazil | Territorial Prelature of Foz do Iguaçu was established (from Diocese of Curitiba and became suffragan of Curitiba) |
| 1926.05.10 | Brazil | Diocese of Jacarezinho was established (from Diocese of Curitiba and became suffragan of Curitiba) |
| 1926.05.10 | Brazil | Diocese of Ponta Grossa was established (from Diocese of Curitiba and became suffragan of Curitiba) |
| 1926.05.10 |  China | Apostolic Vicariate of Xuanhuafu 宣化府 was established (from Apostolic Vicariate of Beijing 北京) |
| 1926.05.11 |  Namibia | Apostolic Prefecture of Cimbebasia was promoted as Apostolic Vicariate of Windhoek |
| 1926.05.12 | China | Apostolic Vicariate of Fenyang 汾陽 was established (from Apostolic Vicariate of Taiyuanfu 太原府) |
| 1926.06.21 | Brazil | Diocese of Cafelândia was established (from Diocese of Botucatu and became suffragan of São Paulo) |
| 1926.07.12 | China | Apostolic Prefecture of Shuozhou 朔州 was established (from Apostolic Vicariate of Taiyuanfu 太原府) |
| 1926.07.12 | Egypt | Apostolic Vicariate of Canal of Suez was established (from Apostolic Vicariate of Egypt) |
| 1926.07.28 | Congo-Kinshasa | Apostolic Prefecture of Basankusu was established (from Apostolic Vicariate of Nouvelle-Anvers) |
| 1926.08.03 |  USA | Diocese of Amarillo was established (from Diocese of Dallas and Diocese of San Antonio and became suffragan of San Antonio) |
| 1926.08.03 | USA | Diocese of San Antonio was promoted as Metropolitan Archdiocese of San Antonio (with suffragan sees Amarillo, Corpus Christi, Dallas, El Paso and Galveston and lost territory to establish Diocese of Amarillo) |
| 1926.08.10 | China | Apostolic Vicariate of Taizhou 台州 was established (from Apostolic Vicariate of Ningbo 寧波) |
| 1926.08.11 | China | Apostolic Vicariate of Haimen 海門 was established (from Apostolic Vicariate of Nanjing 南京) |
| 1926.08.11 |  Cook Islands,  Niue | Apostolic Prefecture of Cook and Manihiki was renamed as Apostolic Prefecture of Cook Islands |
| 1926.12.10 | Brazil | Territorial Prelature of Acre e Purus was renamed as Territorial Prelature of São Peregrino Laziosi no Alto Acre e Alto Purus |
| 1926.12.14 | Congo-Kinshasa | Apostolic Vicariate of Uélé Orientale was renamed as Apostolic Vicariate of Niangara |
