Daniel Astin - who is studying at Huddersfield University - was first reported missing on Friday (May 21).
The 31-year-old has not been seen on campus or at his university accommodation for around a month, according to West Yorkshire Police.
Daniel, from Burnley is described as white, around 5ft 10in tall, of a heavy build with a shaved head and facial hair.
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Det Insp Simon Reddington, of Kirklees CID, said: "We do have growing concerns for Daniel’s welfare and have been carrying out a number of enquiries in Huddersfield and in Burnley to locate him.
"I would ask Daniel or anyone who may have seen him in recent days to contact us and let us know he is ok."
Anyone who has information about Daniel's whereabouts has been asked to contact Kirklees CID on 101, quoting police log number 883 of May 21.
Information can also be given online at www.westyorkshire.police.uk/101livechat.
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