A Little Princess (1977)

Sara Crewe is a bright, kind and imaginative girl attending Miss Minchin's Select Seminary For Young Ladies. Her father, a wealthy military officer with a sizable fortune, makes sure that his daughter has the best clothes, books and toys money can buy. But when Captain Crewe dies his seemingly endless supply of money vanishes, leaving Sara without a penny and the irate Miss Minchin with a large unpaid bill for Sara's education and extravagant upkeep. Since the no-longer-wealthy little girl has become a pauper, she is forced to become a servant at the boarding school where she was once a pupil.
Based on the novel A Little Princess by Frances Hodgson Burnett