Robert Johannes Lavonius (16 December 1879 — 2 January 1967) was a Finnish businessman, engineer and vuorineuvos. Lavonius did his early career in German, Swiss, United States and Canadian companies, and Finnish Suomen Metalliteollisuuskonttori and Tampereen Pellava ja Rauta-teollisuus Oy. He worked in managing positions in Kone ja Silta and its subsidiaries Atlantic Rederi, Hietalahti Shipyard and Engineering Works and Crichton-Vulcan; he became company manager in 1929. In 1936 Kone ja Silta was taken over by Wärtsilä. As Lavonius could not get along with manager Wilhelm Wahlforss, he left the company and worked in arms industry until end of World War II.