Roughly three-quarters of Czechs agree with the possibility to conclude marriage irrespective of sexual orientation and three-fifths are for the gay and lesbian couples adopting children from institutes, according to a poll conducted by the Median agency.
The poll represents a shift from 2016 when support stood at 68 percent.
Meanwhile, 61 percent believe same-sex couples should be able to adopt children, where just two years ago respondents had been evenly split.
Same-sex couples are currently permitted to enter registered partnerships in the Czech Republic under a law passed in 2006, but gay couples are not afforded the full right of marriage.
The country does not permit joint adoption by same-sex couples, although a 2016 court ruling struck down a ban on people in registered partnerships adopting as individuals.
If marriage equality does pass in the Czech Republic, it would be the first post-Soviet country to embrace the measure.