Russian officials will be able to fine protest organizers if young people take part in their demonstrations, under a bill signed off by lawmakers in parliament's lower house on Tuesday.
Opposition leader Alexei Navalny, whose anti-corruption activism has attracted a youthful following, said on Twitter the law was proposed "specifically for me".
Anyone who arranges an unsanctioned protest in which under-18s take part will face a fine of up to 50,000 ($750) rubles or up to 15 days in jail, according to the parliament's website.
Repeat offenders can be fined up to 300,000 rubles ($4,500) or be imprisoned for a month, under the bill which is all but certain to be approved by the upper house of parliament and President Vladimir Putin.
Navalny's anti-Kremlin protests in recent years have seen thousands take to the streets, including many minors.
Last year authorities claimed that young people had been lured to demonstrations with promises of financial rewards.
Navalny, a 42-year-old Yale-educated lawyer, has himself been repeatedly jailed for calling unsanctioned protests.
Lev Ponomaryov, a 77-year-old rights activist, was this month jailed for 16 days after calling for protests against a growing crackdown on youngsters.
Authorities have charged young people with "extremism" for sharing humorous memes online and have cancelled rap concerts, in a move some have compared to the Soviet blacklisting of rock musicians.