A federal judge has conditionally granted class-action status on behalf of a group of Hearst Corp. interns who allegedly weren't paid for their work at 19 of the company's magazines, including Harper's Bazaar, Cosmopolitan and Good Housekeeping.

Xuedan Wang, a former intern at Harper's Bazaar from last August to December, sued Hearst earlier this year, alleging the company violated federal and state labor laws by misclassifying her and other workers as unpaid or underpaid interns, rather than employees. As a result, they were...