Third-place Derby were looking to move to within two points of second-placed Burnley who face Blackburn in the Lancashire derby on Sunday.
Yeovil Striker Ishmael Miller struck either side of half-time to end the Owls' impressive away run and earned the Glovers back-to-back wins at Huish Park for the first time this season.
Those results mean that Charlton Athletic, on FA Cup duty this weekend, slip to the bottom of the table.
Ravel Morrison struck a double as he returned to St Andrew's to haunt Birmingham and pave the way for QPR's first win in six games in a 2-0 triumph.
Morrison, who resurrected his career at Birmingham last season, scored from a splendid 14th-minute free-kick and netted an easy second in the 72nd minute to plunge his former club to their 12th successive home game without a win.
Lewis Grabban's 14th Championship goal of the season earned Bournemouth a 1-0 victory over Blackpool, who extended their winless streak to 18 games in all competitions.
The former Rotherham striker scored from the penalty spot early in the second half to secure the Cherries' first away win in five games, but the result piled further misery on the Seasiders.
Royston Drenthe fired a second-half equaliser as Reading fought back strongly to earn a 1-1 draw at fellow play-off contenders Brighton.
Doncaster bounced back from their worst defeat of the season with a sparkling display in a hard-fought 2-0 derby win over Huddersfield.
Barnsley 1 - 0 Nottm Forest
Birmingham 0 - 2 QPR
Blackpool 0 - 1 Bournemouth
Brighton 1 - 1 Reading
Derby 0 - 1 Millwall
Doncaster 2 - 0 Huddersfield
Leeds 1 - 5 Bolton
Middlesbrough 2 - 0 Ipswich
Yeovil 2 - 0 Sheff Wed
- Sports & Recreation
- Ishmael Miller