SAN FRANCISCO – The California Supreme Court ruled yesterday that a beauty-products company may be held liable for ordering a supervisor to fire a female employee because she wasn’t “good looking enough” and to replace her with someone “hot.”

The 4-2 ruling significantly expands protections for workers who refuse to follow orders they reasonably believe violate anti-discrimination laws. The court held that workers are protected from retaliation even if they fail to report the alleged discrimination to the company and even if the order was not unlawful.

Elysa Yanowitz, a regional sales manager for L’Oreal USA , said her boss ordered her to fire a female sales associate with a strong performance record because the dark-skinned employee was not attractive enough. After Ms. Yanowitz repeatedly refused, she said the company retaliated against her. Ms. Yanowitz eventually left L’Oreal on a disability leave because of stress.

Ms. Yanowitz contended that her boss’s order was illegal sex discrimination because male sales associates were not required to be attractive.

The court refused to decide whether discrimination on the basis of looks was illegal under state law. But the court agreed with findings by other courts that an appearance standard that is applied to one gender and not the other is sex discrimination unless the differential treatment can be justified as a legitimate occupational qualification.

“We believe it is clear that such unjustified disparate treatment … would constitute unlawful sex discrimination” under California law, Chief Justice Ronald George wrote for the court.

Justices Ming Chin and Marvin Baxter dissented, arguing that Ms. Yanowitz could not seek compensation for retaliation because she failed to report the alleged discrimination to the appropriate company officials.

“This case thus presents the question of whether a person can be a whistleblower without blowing the whistle,” Justice Chin wrote. “At least in this case, where the personnel order was not clearly unlawful, I would say no.”

Former California Supreme Court Justice Joseph Grodin, who argued the appeal for Ms. Yanowitz, said the ruling sends a message to employers that “workers are allies in the battle against discrimination” and will be protected for refusing to obey potentially illegal orders.

Ms. Yanowitz, 59, who worked for the cosmetics and fragrance company for more than 17 years, was gratified by yesterday’s ruling. “I hope this case gives other managers the courage to do what is right for those who report to them,” the Northern California woman said.

Lawyers for L’Oreal could not be reached for comment.