Commissioners v. Sellew was a United States Supreme Court case that addressed the issue of whether a state could tax the income of a non-resident. The case involved a dispute between the Commissioners of the Town of New Haven, Connecticut and the plaintiff, William Sellew. Sellew was a resident of New York and owned property in New Haven. The Commissioners of New Haven had assessed a tax on Sellew's income from the property, which Sellew refused to pay. Sellew argued that the tax was unconstitutional because it violated the privileges and immunities clause of the Fourteenth Amendment. The Supreme Court held that the tax was constitutional. The Court reasoned that the tax was not a burden on interstate commerce, and that it did not violate the privileges and immunities clause. The Court also noted that the tax was not discriminatory, as it applied equally to all non-residents. In conclusion, the Supreme Court held that the tax was constitutional and that the Commissioners of New Haven had the right to assess the tax on Sellew's income from the property.

In Commissioners v. Sellew, the Supreme Court was asked to decide whether a tax imposed by the state of Massachusetts on certain railroad and telegraph companies was constitutional. The majority opinion held that it was not, as it constituted an unconstitutional burden on interstate commerce in violation of Article I, Section 8 of the Constitution. Justice Field dissented from this decision, arguing that while Congress has exclusive power over interstate commerce under Article I, Section 8 of the Constitution, states are still allowed to impose taxes upon such activities so long as they do not discriminate against out-of-state interests or interfere with federal regulation. He further argued that since there were no allegations made about discrimination or interference in this case and since all parties involved had consented to pay their respective taxes without objection for many years prior to litigation being brought forth before the court; he believed that there should be no reason why these taxes should now be declared unconstitutional.