Authorities say 43-year-old Matthew Thoke was hiking along the High Sierra Trail Between Kaweah Gap and Crescent Meadow.
He was last seen around 1 o'clock Wednesday afternoon when he split from his group and walked off-trail.
Thoke has brown hair, brown eyes, and is six feet tall.
He was carrying a black overnight backpack and is believed to be wearing a brightly colored T-shirt and shorts.
Rangers are asking anyone who hiked along the High Sierra Trail in the last few days to contact them.