We examine the effect of public policy on the growth of Internet use. Using a decentralized country—Spain—as an example, we compare the 17 Spanish regions to test different Internet policy designs, taking into account the quality and number of specific programs promoted by regional governments, as well as the presence or absence of strategic planning in each region. We treat the percentage of Internet users as a dependent variable to compare its diffusion in different territories. Our findings show that educational levels and economic differences explain about half of the variations observed. Furthermore, the regional policies play a significant role in explaining regional variations. We investigate which public policy instruments are more significant for the development of the Internet, and find that focused policy intervention and complex policy initiatives are more significant than other policy instruments in explaining the increase in the percentage of Internet users.