To Tailor Schedules, Students Log In to Online Classes

Some students crave a class that their school doesn’t offer. Others want to fortify their high school transcripts before college-admissions officers review those records.

Jessica B. Byerly, 17, had her own reasons for signing up for an online course as a junior: Her schedule was so packed with academic classes the previous year, she was forced to give up her lunch period. She wanted it back.

"I was stressed out all the time," recalled Ms. Byerly, now a senior at University High School in Normal, Ill. Taking an online Advanced Placement literature and composition course outside the traditional school day "gave me a lot of options," she said. "I liked the...