The punishment comes for comments made by the Villa boss following a game against Chelsea at Stamford Bridge.
Lambert was critical of the match officials after Chelsea defender John Terry appeared to punch the ball inside his own penalty area.
However, no spot-kick was awarded to Villa, who lost 2-1 to their hosts.
"I'm pretty sure that if it had been down the other end, it would have been given," Lambert said after the match.
A statement from the FA read: "Following an Independent Regulatory Commission hearing, Aston Villa manager Paul Lambert has been fined £8,000 in relation to post-match media comments he made after his side's game against Chelsea on 21 August 2013.
"The misconduct charge, which Lambert admitted, was that the comments implied the match referee was motivated by bias; and/or brought the game into disrepute, in contravention of FA Rule E3 (1)."
Meanwhile, Nottingham Forest manager Billy Davies has been handed a one-match touchline ban and fined £2,000 for comments made after their 2-1 defeat at Wigan last weekend.
Davies walked onto the DW Stadium pitch and gestured in the direction of referee Craig Pawson, with the Scotsman seemingly upset by Pawson's refusal to award his side a second-half penalty when Chris Cohen clashed with Roger Espinoza.
A statement on the FA website read: "Nottingham Forest manager Billy Davies has been fined £2,000 and given a one-match touchline suspension after he admitted a breach of FA Rule E3 in that his language and/or behaviour following the end of his side's game against Wigan Athletic on 31 August 2013 amounted to improper conduct."