We conducted a field experiment in a sales firm to test whether improving knowledge flows between coworkers affects productivity. Our design allows us to compare different management practices and to isolate whether frictions to knowledge transmission primarily reside with knowledge seekers, knowledge providers, or both. We find large productivity gains from treatments that reduced frictions for knowledge seekers. Workers who were encouraged to seek advice from a randomly chosen partner during structured meetings had average sales gains exceeding 15%. These effects lasted at least 20 weeks after the experiment ended. Treatments intended to change knowledge providers’ willingness to share information, in the form of incentives tied to partners’ joint output, led to positive—but transitory—sales gains. Directing coworkers to share knowledge raised average productivity and reduced output dispersion between workers, highlighting the role that management practices play in generating spillovers inside the firm.