The Japanese macaque found a way out of its enclosure at Highland Wildlife Park near Kingussie on Sunday morning.
Staff at the park, run by the Royal Zoological Society of Scotland (RZSS), urged the public not to approach the primate.
The macaque was reportedly spotted eating nuts from a bird feeder in the nearby village of Kincraig on Sunday morning.
Resident Carl Nagle told BBC Scotland News: "I looked out the window and there he was, proud as punch, standing against the fence eating nuts that had fallen down from one of the bird feeders."
Highland Wildlife Park confirmed the monkey's escape on Facebook and a search has been launched.
Darren McGarry, head of living collections at RZSS, said: “We can confirm one of our Japanese macaques escaped from its enclosure this morning.
“Our charity has set up a team who are working to secure the monkey safely and as quickly as possible.
“If members of the public encounter the macaque they should contact email@example.com with more information and do not approach it.”
The wildlife park houses a “large group” of Japanese macaques after successfully breeding the species.
The Japanese macaque, also known as the snow monkey, is the most northerly living non-human primate, according to the RZSS.