Browning, 23, will be reunited with Sunderland boss Simon Grayson, having spent the second half of last season on loan at Preston under Grayson.
The England Under-21 international has made nine appearances for Everton since his debut in September 2014.
Sunderland signed another Everton defender, Brendan Galloway, on a season-long loan deal on Wednesday.
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Everton defender Tyias Browning has joined Championship side Sunderland on a season-long loan deal.