This paper examines knowledge spillovers across ethnic boundaries. Using the case of skilled German immigrants in the Russian Empire, we study technology adoption among Russian peasants. We find that distance to German settlements predicts the prevalence of heavy iron ploughs, fanning mills and wheat sowing among Russians, who traditionally ploughed with a light wooden ard and sowed rye. The main channel of technology adoption was German fairs. We show that heavy ploughs increased the labor productivity of Russian peasants. However, communication barriers precluded Russians from adopting skill-intensive occupations like blacksmithing, mechanics, carpentry, and other crafts. The results suggest that skilled immigrants may enhance local development through the introduction of advanced tools without transmitting their skills to a receiving society.