At a tumbledown wooden shack in a fishing village on the shores of Lake Victoria in Uganda, 17-year-old Margaret Babirye cuddles her baby at lunch break before dashing back to school — a right she could only have dreamed about before Uganda’s reforms.

Babirye is one of thousands of girls benefiting from a new Ugandan government policy encouraging girls who have given birth to return to class, part of a broader trend documented by Human Rights Watch by which African nations are encouraging young mothers back to school.

“I made a mistake giving birth while still young and in school, but God has big plans for me, so I decided to return to school,” aspiring nurse Babirye said as she fed biscuits to her daughter, one-year-old Pretty Miracle Laamalu...