António Baltasar Marcelino (21 September 1930 – 9 October 2013) was a Portuguese Roman Catholic bishop of Aveiro.
Marcelino was born on 21 September 1930 in Castelo Branco, Portugal.
He was ordained on 9 June 1955, was named bishop in 1975, and retired in 2006.Marcelino died of an undisclosed disease on 9 October 2013, aged 83, at a hospital in Aveiro.