Henry Joseph Dabzac (1737–12 May 1790) was an Irish academic.

He was Donegall Lecturer in Mathematics (1764-1769) and gained his BD (1767) and DD (1772).

He was Archbishop King's lecturer (1773, 1779), and gained his MA in 1760.

In March 1774 he married Catherine Pigou and they had twelve children, of whom four died in infancy.

[citation needed] Dabzac was the librarian at TCD from 1785 until his death.