| Type: | Bishop |
| Honorific-Prefix: | Venerable |
| Leonardo Castellanos y Castellanos | |
| Bishop of Tabasco | |
| Church: | Roman Catholic Church |
| Archdiocese: | Yucatán |
| Diocese: | Tabasco |
| See: | Tabasco |
| Appointed: | 7 August 1908 |
| Term Start: | 5 October 1908 |
| Term End: | 19 May 1912 |
| Predecessor: | Francisco Maria Campos y Angeles |
| Successor: | Antonio Hernández y Rodríguez |
| Ordination: | 20 March 1886 |
| Ordained By: | José María Cázares y Martínez |
| Consecration: | 27 September 1908 |
| Consecrated By: | Cardinal Giuseppe Ridolfi |
| Rank: | Bishop |
| Birth Name: | Leonardo Castellanos y Castellanos |
| Birth Date: | 6 November 1862 |
| Birth Place: | Ecuandureo, Michoacán de Ocampo, Mexico |
| Death Place: | Villahermosa, Tabasco |
| Nationality: | Mexican |
| Feast Day: | May 19 |
| Venerated: | Roman Catholic Church |
| Saint Title: | Venerable |
Leonardo Castellanos y Castellanos (November 5, 1862 in Ecuandureo, Michoacán − May 19, 1912) was a Mexican Roman Catholic bishop.
Ordained to the priesthood on March 20, 1886, Castellanos y Castellanos was named bishop of the Roman Catholic Diocese of Tabasco, Mexico in 1908 and died in 1912 while still in office.[1]