I investigate the effects of switching costs on the market outcome in network industries using a dynamic duopoly model of price competition in the presence of an outside option. I find that the role of switching costs depends on network effects and the outside option. Without a viable outside option, high switching costs can neutralize the tendency towards high market concentration associated with network effects, but with a viable outside option, switching costs increase market concentration. Furthermore, switching costs lower prices if network effects are modest and there exists a viable outside option, but generally raise prices otherwise.