In 1879, then 23-year-old Maurice Koechlin became the lead structural engineer of Gustave Eiffel’s construction company founded 13 years before. Together, they pushed the boundaries of steel and iron structural design. They were responsible for the design of the Garabit viaduct (1879-1884), the Tarde viaduct (1881-1884), the inner reinforcement of the Statue of Liberty (1881-1886) and the 300 meter-high tower in Paris (1884-1889). In 1900, Koechlin succeeded Gustave Eiffel to head the company, a position he held until his retirement in 1940. Whereas Maurice Koechlin’s engineering works are known by many and considered as masterpieces, very little is known about his written scientific contribution. This paper first attempts to draw a comprehensive list of Koechlin’s publications. A total of 28 have been identified among which one book and 14 papers provide original findings on struc-tural engineering science. Written between 1884 and 1925, they address the resolution of specific structural problems using graphic statics or numerical methods, they develop the design process of structures built by the Eiffel Company or they describe pioneering implementations for steel. As this original survey sheds new lights on Koechlin’s research interests and their chronolo-gy, the paper also restates Maurice Koechlin’s influence on the introduction of graphic statics in French-speaking Europe and further contextualizes the collaboration between Maurice Koechlin and Gustave Eiffel and the contribution of Maurice Koechlin to the Société de constructions de Levallois-Perret.