Today, many governments are considering the exploration and production of unconventional resources, shale gas in particular, for reasons of security of supply and reduction of import dependency. Large-scale development of these resources promises to significantly lower import dependency of gas supply of many countries. Whether the promise will be met remains uncertain though, not only because of uncertain resources, technological challenges, and environmental concerns, but also because of the interdependence, complexity and uncertainty of gas markets. Modelling and simulation may therefore be required to assess the resulting economic implications of global shale gas development. In this study, System Dynamics and Agent-Based models are simultaneously deployed under deep uncertainty to discover and explore plausible scenarios for the development of shale gas and the effects on regional gas markets and regional import dependency. Among else, it is shown that regional economic growth is likely to have a larger impact on gas import dependency than the actual size of shale gas resources.