Harmanus is a masculine given name. Notable people with the name include:
Harmanus Bleecker (1779–1849), American attorney, politician and ambassador Harmanus Bleecker Library, Albany, New York, United States Harmanus B. Duryea (1815–1884), American lawyer, politician, and militia officer Harmanus Peek (1782–1838), American lawyer and politician (1765–1791), Dutch painter
See also Harman Hermanus (name)