José Mariano de Conceição Vellozo (also called José Mariano da Conceição Veloso) (1742 – 1811) was a Brazilian botanist who catalogued specimens, for example: Cedrela fissilis Vell. in Florae Fluminensis (1825–27; 1831). He was born in Tiradentes, formerly called São José do Rio das Mortes, state of Minas Gerais; and died in Rio de Janeiro, state of Rio de Janeiro. While at the University of Coimbra in Portugal in the 1790s he worked with Martim Francisco Ribeiro de Andrada in translating works on mineralogy and agriculture.
- Dickson James; Vellozo (ed.) Plantarum Cryptogamicarum Britanniae Lusitanorum Botanicorum (1800)
- Florae Fluminensis (1825–27; 1831) Main work
- O Fazendeiro do Brasil (1798–1806)
- Carauta, J. P. P. The Text of Vellozo's Flora Fluminensis and Its Effective Date of Publication Taxon, Vol. 22, No. 2/3 (May, 1973), pp. 281–284.