Prior work has extensively studied how investing in R&D and building a technology portfolio relate to superior firm performance. However, the value of a firm’s technology portfolio should also be driven by the degree to which it is more unique and technologically differentiated from other firms. To study this research question, we develop a new method to characterize firm technology based on the semantic content of patent portfolios that allows us to map a firm’s competitive position in the technology space relative to all other firms and to measure the differentiation of a firm’s technology portfolio. Using a large panel of U.S. public firms from 1980 to 2015, we find that technology differentiation has a strong positive and long-lasting relation with firm performance. Moreover, differentiated firm technology is particularly valuable in industries with higher R&D intensity and with stronger product market competition. We provide open access to all code and data to measure the technology similarity and the technology differentiation of U.S. public firms