Freshwater streams receive nutrients, contaminants, and organic material from their catchment, which are then transported downstream. Here we develop contaminant spiraling as a unifying conceptual model within the study of the fate and effects of contaminants in aquatic-terrestrial meta-ecosystems throughout stream networks. We start by taking an expansive view of nutrient spiraling, adding concepts of ecotoxicology, food web theory, ecological subsidy theory, the River Continuum Concept, and contaminant fate and transport modeling to characterize a multidimensional contaminant spiral with components of spiraling length, width, and transport velocity. To provide a broad context for the types of biological responses that might drive contaminant spiraling, our conceptual model distinguishes between contaminants considered non-toxic and toxic to the base of the food web at environmentally relevant concentrations. For example, if microbial communities are not directly affected by non-toxic contaminants, then uptake in those biofilms and emerging aquatic insects should increase with a contaminant’s propensity to bioaccumulate, leading to wider, shorter spirals. In contrast, toxic contaminants can reduce biofilms, affecting the contaminants’ transport within aquatic-terrestrial meta-ecosystems. At high concentrations, toxic contaminants are expected to increase spiral length, reduce spiraling width, and reduce insect-mediated contaminant flux to land. Position in the stream network will also affect contaminant spiraling by influencing the probability of exposure to these contaminants as well as the productivity and basis of production of the stream and riparian ecosystems. Testing these and further hypotheses derived from our conceptual model is instrumental to understanding the spatio-temporal dynamics of contaminants’ fate and effects within aquatic-terrestrial meta-ecosystems, ultimately directing respective policy decision making and management.