Some schools in Russia are preparing fake schedules to conceal their efforts to shun patriotic education classes. Some parents school their children at home. Others try to help young people navigate a school system in which they say propaganda is pervasive.

Faced with what they say is an ever-growing flood of misinformation about the war in Ukraine in Russian schools, parents and teachers who oppose the conflict say they are waging a desperate battle for the minds of their children.

“You constantly have to play cat-and-mouse with the school: New things keep coming up like rounds of gunfire,” said Varvara, 42, a mother of four from St. Petersburg. Like other people across Russia reached by telephone, Varvara asked that her surname not be used in this article to avoid retribution from the authorities.

She cited activities that she saw as bolstering the war effort: a music teacher who held a contest to perform Russian military songs; her teenage son’s school outing to hear a pro-war talk by a veteran of the Soviet Union’s invasion of Afghanistan; classes that portray Russia as a victim and the West as an enemy.

When President Vladimir V. Putin of Russia introduced “patriotic education” in schools near the start of the full-scale invasion of Ukraine in 2022, many critics saw it as a marginal endeavor that would work only in economically depressed regions, where schooling was already poor.

Three years on, the Kremlin’s efforts to indoctrinate children have taken deep root in most schools across Russia, parents and analysts say.