In this paper, we present the design and the results of a comparative study that evaluated the success of a transfer of an online-teaching resource between two universities, one in Germany and one in the USA. The teaching resource is an online physics lab that has been used in the physics education of medical students in Germany since 2003. The online lab covers geometrical optics and the optics of the human eye using interactive screen experiments. It was translated and transferred to a university in the USA where it was used and evaluated with a group of pre-health students. In a cross-national study, students' backgrounds (demographic data, selected cognitive abilities, previous knowledge, and self-concept in physics), students' attitudes towards the online lab, and their learning gain were compared. The results show significant differences between the German and the US cohorts with regard to students' backgrounds. Despite these differences, the outcomes are similar, with slightly higher leaning gains for the US students. Students' attitudes towards the online lab are similar in both countries but tend to be more positive among the US students. The results indicate that the transfer of the online lab to another educational system was successful.