As a concept and phenomenon, ‘flex crops and commodities’ feature ‘multiple-ness’ and ‘flexible-ness’ as two distinct but intertwined dimensions. These key crops and commodities are shaped by the changing global context that is itself remoulded by the convergence of multiple crises and various responses. The greater multiple-ness of crops and commodity uses has altered the patterns of their production, circulation and consumption, as novel dimensions of their political economy. These new patterns change the power relations between landholders, agricultural labourers, crop exporters, processors and traders; in particular, they intensify market competition among producers and incentivize changes in land-tenure arrangements. Crop and commodity flexing have three main types – namely, real flexing, anticipated/speculative flexing and imagined flexing; these have many intersections and interactions. Their political-economic dynamics involve numerous factors that variously incentivize, facilitate or hinder the ‘multiple-ness’ and/or ‘flexible-ness’ of particular crops and commodities. These dynamics include ‘flex narratives’ by corporate and state institutions to justify promotion of a flex agenda through support policies. In particular, a bioeconomy narrative envisages a future ‘value web’ developing more flexible value chains through more interdependent, interchangeable products and uses. A future research agenda should investigate questions about material bases, real-life changes, flex narratives and political mobilization.