The Afterschool Alliance says about a third of Minnesota students - 300,000 - are left unsupervised after school at least once a week. Those kids spend a weekly average of seven hours on their own.
The rate has improved from five years ago, and the report gives the state credit for that progress.
But University of Minnesota researcher Dale Blyth notes the room left for improvement. Poorer children, for example, are less likely to be in after-school programs.
"The more urban, the more disadvantaged, the more rural and isolated the communities are, the harder it is for parents to find things for their young people to do that are constructive and challenging and engaging to them," he said.
Twelve percent of Minnesota children are enrolled in after school programs. That mark is lower than the national average but higher than Minnesota's rate five years ago.
"Minnesota is making some progress, and can be proud of that," said Afterschool Alliance Executive Director Jodi Grant, in a statement. "But the great majority of Minnesota parents who want their kids in afterschool programs aren't able to find them, usually because programs aren't available, they can't afford the fees, or transportation issues make it impossible."