Meyer et al. v. Arthur was a United States Supreme Court case that addressed the issue of whether a state could constitutionally limit the number of hours a person could work in a day. The case was brought by a group of workers who had been employed by a company in the state of Ohio. The workers argued that the state's law limiting the number of hours they could work in a day was unconstitutional. The Supreme Court held that the state's law was unconstitutional. The Court reasoned that the law violated the Fourteenth Amendment's Due Process Clause, which protects individuals from arbitrary government action. The Court noted that the law was not necessary to protect the health and safety of the workers, and that it was an unreasonable restriction on the workers' right to contract. The Court also noted that the law was not necessary to protect the public interest, as the workers were already being paid a fair wage. The Court's decision in Meyer et al. v. Arthur established that states cannot limit the number of hours a person can work in a day without a compelling reason. This decision has been cited in numerous subsequent cases involving the regulation of labor.

In Meyer et al. v. Arthur, the Supreme Court was tasked with deciding whether a state court could issue an injunction to prevent a party from enforcing their rights under a contract that had been formed in another state. The majority opinion held that such injunctions were not permissible because they would interfere with the right of parties to enforce contracts as provided by law and would be contrary to public policy. Justice Field dissented, arguing that states have the power to protect their citizens from being taken advantage of by out-of-state parties who may attempt to use unfair or illegal means for enforcement of contracts made outside its borders. He argued further that this power should extend even if it involves interfering with contractual obligations created elsewhere since it is within each state's police powers and does not conflict with any federal laws or constitutional provisions.