A liquid ejection head includes a plurality of recording element substrates that each include an energy generating element generating energy utilized for ejecting a liquid and that each have a supply port through which the liquid is supplied to the energy generating element, a plurality of support members that each have a flow passage communicating with a corresponding one of the supply ports and that each support a corresponding one of the plurality of recording element substrates, a base substrate that supports the plurality of support members, and a heat insulating member disposed between the flow passages and the base substrate. In the liquid ejection head, a thermal conductivity of the support members is equal to or greater than a thermal conductivity of the recording element substrates, and a thermal conductivity of the heat insulating member is less than a thermal conductivity of the base substrate.