Agricultural trends, including a global rise in herbicide-resistant weed genotypes and a growing demand for food produced with minimal external synthetic inputs, are driving producer interest in reducing reliance on herbicides for weed management. An improved understanding of weed ecology can support the design of weed-suppressive agroecosystems. This chapter explores current scientific knowledge of ecological levels of organizations, including populations, communities and agroecosystems, relevant to the study and management of agricultural weeds. A population dynamics framework for targeting management tactics to specific weed life stages is presented, and its applicability to solving real-world weed management problems is demonstrated in a case study of mitigating the invasive potential of an exotic bioenergy crop species.