A rich and wide variety of fluid dynamic processes occur in fjords. Although a fjord may at one level be simply defined a glacially formed coastal inlet, this simple definition belies a huge range of geomorphological manifestations and environmental forcing conditions. It is the interplay between geomorphology and environmental forcing which defines the relative importance of differing physical fluid processes within a given fjord. In this chapter we present a non-mathematical review of the dominant physical processes which are found to occur in fjordic systems, how their relative importance may depend on geomorphology and forcing, and how, in turn, the dominant physical processes effect circulation and sediment distribution. Our aim is to provide the non-physical oceanographer with an insight into the rich and varied fluid dynamical processes presented to us by the fascinating ‘mini-ocean’ geo-type generically referred to as a fjord.