Democratic Party chairman Lo Kin-hei was on Wednesday acquitted of taking part in an unlawful assembly in Tsim Sha Tsui during the 2019 social unrest.
The prosecution had alleged that Lo was among protesters who gathered near the Science Museum on November 18, 2019.
But District Court judge Ernest Lin ruled that the politician had not taken part in clashes between protesters and the police, and that he did not have any interactions with the protesters.
Lin said the prosecution had not been able to prove beyond reasonable doubt that Lo participated in the unlawful assembly.
Three other people charged in the same case were convicted of unlawful assembly, while a fifth defendant was found guilty of possessing an offensive weapon.