Yes. L-2 children may attend school for the duration of the principal's status without a separate student visa. They may not work, and their L-2 status ends at 21 or on marriage.
School is covered; the timing of the assignment and the child's age are the variables
Hypothetical example: the chemist's daughter is 16 and two years from graduation, and the assignment is expected to last eighteen months to two years. She may be admitted as an L-2 dependant and enrol in the local school; districts generally ask for proof of residence and immunization records rather than immigration documents, but keep her I-94 record available. She may not take a part-time job. If the assignment ends before graduation, the family decides whether the mother extends, the daughter returns to Saskatchewan to finish, or the daughter changes to student status, which has its own requirements and costs. If the assignment runs long, the daughter's 21st birthday ends L-2 eligibility and she would need her own status to remain. The chemist's husband is employment-authorized incident to L-2 status and may work from admission. Plan the school calendar and the petition timeline together.
Hypothetical example: a fibre-optic sensor specialist is assigned for four years, and her 20-year-old son expects to begin a U.S. college program after he arrives. His passport, birth record, and expected age on each admission decide whether dependent classification will still be available; admission alone does not preserve it after age 21. The family should price an independent student route before relying on an extension. The specialist herself needs one qualifying year abroad in the three years before filing or admission, and L-1B status reaches a five-year maximum.