Iago Aspas opening the scoring in the ninth minute and added a second on the half hour after Alberto Bueno had levelled from the penalty spot in the 12th minute.
A right-footed shot by Álex López in the 52nd minute sealed the points for the hosts.
Celta are in 15th place, just two points above the relegation zone with a record of five wins, 10 losses and three draws after 18 games.
Real Valladolid have now recorded a record of six wins, eight losses and four draws this season, which puts them in 11th place, only six points above the relegation zone.
Celta had 48.6% of possession during the victory.
Celta had 14 shots, including six on target.
Hugo Mallo's 16 passes to Álex López were the most of any Celta team-mates during the match.
Real Valladolid had five shots, including four on target.
Rubén Peña made his mark on the match for Real Valladolid after coming on for Bueno in the 56th minute, as he took two shots.
Bueno had three shots for Real Valladolid, more than any of his team-mates.