A metal-clad laminate includes an insulating layer including a cured product of a resin composition, and a metal foil disposed on a principal surface of the insulating layer. The resin composition includes a polyphenylene ether copolymer and a thermosetting curing agent, the polyphenylene ether copolymer having an intrinsic viscosity measured in methylene chloride at 25° C. of between 0.03 dl/g and 0.12 dl/g, inclusive. And the polyphenylene ether copolymer has, at a molecular terminal, a group represented by formula (1) or formula (2) at an average number of 1.5 to 3 per one molecule. Further, the metal foil has a first surface that is in contact with the insulating layer, the first surface having a 10-point average roughness (Rz) of 2.0 μm or less. And the metal foil includes a barrier layer disposed at a side of the first surface, the barrier layer containing cobalt.