The Portuguese coach had initially been banned for one game with a further one-game ban suspended for three years, but European football's governing body has now scrapped the suspended sanction.
Mourinho will in any case be able to return to the dugout following Real's final group stage game at home to Auxerre on Wednesday.
UEFA specified that the original punishments were for "improper conduct".
Midfielder Xabi Alonso and right-back Sergio Ramos were both sent off at the end of Real's 4-0 win in Amsterdam on November 23 after receiving their second yellow cards for blatant acts of time-wasting.
The dismissals mean they are banned for Real's final 'dead rubber' Group G match with Auxerre and Spanish press speculated that they had deliberately got sent off to give themselves a disciplinary clean slate in the last 16.
UEFA's appeals committee on Monday also decided to reduce the fines handed down to Mourinho and his club.
Mourinho's fine was reduced from 40,000 to 30,000 euros, with Real's fine falling to 100,000 euros from 120,000 euros.
The fines given to Alonso and Ramos -- 20,000 euros each -- were not changed, while Iker Casillas and Jerzy Dudek's 5,000 euros fines were also unaffected.
Goalkeeper Casillas and reserve keeper Dudek were fined after being captured on television apparently passing messages to Alonso and Ramos from the dugout.