| Jurisdiction: | Diocese |
| Merlo-Moreno | |
| Latin: | Dioecesis Merlensis-Morenensis |
| Local: | Diócesis de Merlo-Moreno |
| Country: | Argentina |
| Metropolitan: | Mercedes-Luján |
| Province: | Mercedes-Luján |
| Area Km2: | 301 |
| Population: | 850,591 |
| Population As Of: | 2004 |
| Catholics: | 701,737 |
| Catholics Percent: | 82.5 |
| Denomination: | Catholic |
| Sui Iuris Church: | Latin Church |
| Rite: | Roman Rite |
| Established: | 13 May 1997 (years ago) |
| Cathedral: | Parroquia Catedral Nuestra Señora del Rosario |
| Patron: | Our Lady of Guadalupe |
| Bishop Title: | Bishop |
| Bishop: | , C.M.F. |
| Map: | Diocesi di Merlo-Moreno.jpg |
The Roman Catholic Diocese of Merlo-Moreno (erected 13 May 1997) is in Argentina and is a suffragan of the Archdiocese of Mercedes-Luján, having had change of metropolitan from Buenos Aires in 2019.
The patroness is the Blessed Virgin Mary of Guadalupe.
The partidos (departments) that fall into the diocese are Merlo and Moreno.