This thesis is about four small IT service firms with offices in Sweden and India. These four service firms set out to interact and collaborate between the offices, some more intensely and frequently than others. In the process of their internationalisation, they need to find ways, or to learn, how to collaborate in an international setting, including making use of physical as well as social proximity. In Proximity and Learning in Internationalisation - small Swedish IT firms in India, Westermark combines a discussion on proximities and processes of learning to present a more thorough understanding of how social proximity can develop over time, and furthermore, in what way social proximity matters for service firms working in an international setting. The qualitative exploration of the process of learning is inspired by 'communities of practice', and Westermark focuses on ways in which individuals at firms through social participation learn to collaborate across distance, and develop a common way of working together in an international setting. This thesis continues the vibrant discussion in economic geography on proximity as more than 'being there' in a physical sense. In this discussion, the understanding of proximity is as a metaphor of closeness, putting more emphasis on individuals and their experiences. In this thesis, experience of closeness is empirically explored through a longitudinal study. This includes trying to operationalise social proximity by exploring the experience of social proximity amongst the individuals at the case firms. More precisely, social proximity is conceptualised as individuals experiencing 'shared social familiarity'.