Ukrainian lawmakers have set May 20 as the day of inauguration of incoming President Volodymyr Zelenskiy.
A total of 315 lawmakers on May 16 voted in favor of the date, while two voted against it.
Earlier in the day, the Verkhovna Rada rejected proposals to hold the inauguration on May 19, the date Zelenskiy has pushed forward.
Zelenskiy defeated President Petro Poroshenko in an April 21 runoff election with more than 73 percent of votes. His opponent received less than 25 percent.
The president-elect, who has suggested he might dissolve parliament and call snap elections, has accused lawmakers of deliberately postponing the swearing-in ceremony.
Under Ukraine's constitution, Zelenskiy would have seven days after his inauguration to dissolve the legislature, whose term is set to end in November.
The 41-year-old has vowed to eradicate Ukraine's widespread corruption and end the war with Russia-backed separatists in the country's east that has killed some 13,000 people since April 2014.
A comedian with no political experience, Zelenskiy will also need to deal with Moscow's takeover of Ukraine's Crimea Peninsula in March 2014.
In Moscow, Kremlin spokesman Dmitry Peskov told reporters on May 16 that he is not aware of "any plans on possible contacts" between Russian President Vladimir Putin and Zelenskiy after his inauguration.
Putin has not congratulated Zelenskiy on his election victory.