Visual attention and visual working memory—VWM; our short-term storage system for visual information—are both inherently limited in their processing capabilities, yet critical to process, and navigate through, our complex visual environments. How is it that attention and VWM support efficient visually guided behaviour? A longstanding theory addressing this question centers on the role of attention in regulating how we use VWM, suggesting that attention serves as a filter to VWM, restricting access to goal-consistent information. The relationship between attention and VWM, however, is more complex than this theory suggests and, moreover, is reciprocal in nature—attention influences the way information is encoded in VWM and, in turn, the contents of VWM guide subsequent attention. As such, the goal of the present thesis is to explore the bidirectional interactions between attention and VWM, with a focus on the flexibility with which the individual mechanisms operate, to extend our understanding of how attention and VWM, although inherently limited, support efficient behaviour. Here I demonstrate that attention regulates the flexible distribution of resources in VWM, but also that its contents can be flexibly prioritized to serve different behavioural needs. Overall, top-down control influences the way attention and VWM interact as part of a larger system that ultimately guides behaviour.