Varifrån kommer den svenska marinens kunskap och erfarenheter om strid till sjöss?   ABSTRACT: A robust doctrine should consist of solid arguments and theory that explain the background in order to give more effect. The Swedish naval doctrine Doktrin för marina operationer (DMarinO) is based on knowledge and experience. The problem is that the doctrine does not mention where Sweden´s knowledge and experience from naval warfare originate. Since Sweden has not been to war in over 200 years it is hard to argue that all knowledge and experience originate from own naval warfare. The issue is whether national or international naval theory can be found in DMarinO.   The thesis is based on the two naval theorists, Landquist and Hughes, who each assigned six variables representing their theory. The purpose of this thesis is to examine whether Landquist and Hughes´s naval theories is found in DMarinO and to increase understanding of naval theories connection to Sweden´s naval doctrine.   The results show that both theories are reflected in DMarinO. Theory from Landquist can be found in a higher degree than theory from Hughes. Therefore it is possible that DMarinO could be influenced by both national and international naval theory, but more research is needed in order to confirm that.     Nyckelord: Landquist, Hughes, militärteori, sjömilitära teoretiker, marin doktrin, DMarinO