Police are appealing for information into the whereabouts of Jean Leveque from Crawley.
The 42-year-old was last seen by a friend around May 8.
He lives in Hawth Close, Crawley, but is often seen in the town centre and Three Bridges area.
He is described as black with short black hair and a pierced right ear.
He is believed to be wearing a fleece jacket and jeans.
PC Mark Green from the Missing Persons team said: “His family are concerned for his welfare as this is very out of character for him to be out of contact for so long.
“We are appealing to anyone who has seen him to make contact with us on 101 quoting serial 1251 of 22/5.”