By stressing that a fear of socialism encouraged the rise of fascism in Italy, the literature places a disproportionate emphasis on the reactive nature of fascism’s popular basis. I apply an interest-based theory to the rise of Italian fascism using data from the first systematic analysis of Fascist electoral strength in the 1921 Italian national legislative election. Results support the hypotheses that the growth of the Fascist vote came at the expense of the Socialists and that much of the support for Italian fascism can be attributed to voters’ rational calculations of their material interests.