This paper explores the relationship between innovation and inequality using the lens of the Schum- peterian growth theory. We develop a two-country growth model with trade in intermediate goods and households' heterogeneity in wealth endowment. In the model, wealth inequality generates income inequality, whereas innovation contributes to shape the endogenous distribution of income. We show that a change in the domestic R&D efficiency (productivity) has both positive and negative effects on income inequality in the domestic economy, with an ambiguous overall impact. To assess which effect empirically prevails, we estimate the relationship between between research productivity and income distribution on a sample of 21 OECD countries using historical data from 1920 to 2015, based on long-run (cointegration) regression. We find a positive association between R&D productivity and a large battery of indicators of income inequal- ity. Furthermore, we assess the short-run sensitivity of inequality to an institutional change that facilitated international patenting, i.e., the adhesion to Patent Cooperation Treaty. Based on the local projection analysis, we simulate the effect of this shock on income inequality and compare it against the counter-factual income distribution induced by a random shock or, alternatively, by the entrance to the European Union by some countries of our sample. This analysis confirms that a more uneven income distribution emerges when research productivitity/efficiency increases.