The Barcelona-based side, meanwhile, were found guilty of 'insufficient segregation' for the last-32 second leg at the RCDE Stadium – but were only given a warning.
Wolves' fine of £8,858 (10,000 Euros) comes after they had previously been warned by Uefa for kicking off late against Slovan Bratislava in the group stage.
Espanyol had not previously been warned about their segregation, so – despite gold and black shirts being dotted around the ground – they have not been handed a fine.
Uefa say the fine 'must be paid within 90 days of communication of this decision'.
Nuno's men lost the game 3-2 in Spain but made it through as they won 6-3 on aggregate.
Wolves have yet to confirm if they will appeal the decision.