The 21-year-old has played three times for Leeds, scoring the winner on his debut against Luton Town in the EFL Cup last season.
He signed a new three-year contract at Elland Road in 2016-17.
Leeds, who have signed Manchester United left-back Cameron Borthwick-Jackson on a season-long loan, have the option to recall Denton in January.
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League Two Port Vale have signed Leeds United left-back Tyler Denton on a season-long loan deal.