This paper studies how trip chaining (combining commuting and shopping or commuting and child care) affects market competition: in particular, pricing and the equilibrium number of firms as well as welfare. We use a monopolistic competition framework, where firms sell differentiated products as well as offering differentiated jobs to households, who are all located at some distance from the firms. The symmetric equilibriums with and without the option of trip chaining are compared. We show analytically that introducing the trip chaining option reduces the profit margin of the firms in the short run, but increases welfare. The welfare gains are, however, smaller than the transport cost savings. In the free-entry long-run equilibrium, the number of firms decreases but welfare is higher. A numerical illustration gives orders of magnitude of the different effects.