Ubirajara Ribeiro Martins (8 July 1932 – 26 May 2015) was a Brazilian entomologist. Martins was born in 1932 in São Paulo, Brazil. He concluded his studies at the Universidade Federal de Viçosa in 1954 with a bachelor's degree in agronomy. Martins then proceeded to work at the Museum of Zoology of the University of São Paulo where he obtained his PhD in 1975 and conducted his research until his death in 2015. He was a colleague of , who named one frog species after him (Bokermannohyla martinsi). He himself described many new species of beetles, and often co-authored other descriptions.