The 34-year-old former England defender has been a regular for the Rams, featuring in 22 games this term.
Warnock, who came through the academy at Liverpool, joined Derby on an 18-month deal from Leeds in January 2015.
"When we found out Stephen was available it really was a no brainer," said manager Gary Caldwell.
"He has vast experience having played extensively at the very top level, but he also has great Football League experience in recent years and I think he will really help the squad at a vital time of the season."
Wigan are second in the table, four points adrift of leaders Burton Albion, who have a game in hand.
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League One promotion hopefuls Wigan Athletic have signed Derby County left-back Stephen Warnock on loan until the end of the season.