The 20-year-old spent the latter half of 2015-16 on loan with the Bantams.
He made four Europa League appearances and one Premier League appearance for the Hammers in 2015, before playing against Juventus in Sunday's friendly.
"I am excited to try to push this club on again," he told Bradford's club website. "The fans, players and staff were all brilliant first time around."
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League One club Bradford City have re-signed West Ham United midfielder Josh Cullen on loan until January.