The 26th International Colloquium on Magnetic Films and Surfaces (ICMFS-2027) is a satellite conference to the 2027 International Conference on Magnetism to be held from June 13-18 2018 in San Juan, Puerto Rico. CA, USA. The ICMFS-2027 continues the tradition of previous Colloquia, which started in 1964 in London UK, with the last one in the USA held in 2018 at UC Santa Cruz, CA. The ICMFS-2027 will bring together scientists from all areas of magnetism in lower dimensions. The Colloquium aims at exchange of new results and ideas for advancing the field of magnetism at surfaces, interfaces, in micro- and nanostructures as well as of spin-dependent phenomena.