The couple helped to raise nearly $35 million (€31.5m) for the country.
"@aplusk & Mila Kunis were among the first to respond to our grief. They have already raised 35 million US dollars & are sending it to @flexport & @Airbnb to help (Ukrainian) refugees", Zelensky wrote via Twitter. "Grateful for their support. Impressed by their determination. They inspire the world".
The president also included the hashtag StandWithUkraine
Calling herself a "proud Ukranian", Mila Kunis' family arrived in the US in 1991.
"Ukrainians are proud and brave people who deserve our help in their time of need", Kunis wrote. "This unjust attack on Ukraine and humanity at large is devastating and the Ukrainian people need our support".
The pair who married in 2015, had earlier promised to match donations made to rental company Airbnb and freight transporter Flexport for up to three million dollars (€2.7m), aiming to raise thirty million dollars (€27m).