Litter decomposition is one of the most basic ecosystem processes in small streams and other ecosystems. As a result, it has been much studied over the past three decades and fundamental features of the process and ecosystem functioning in general have been discovered. Are the lessons learnt applicable beyond streams? Have they cross-fertilized understanding of litter decomposition in forests, grasslands and marine ecosystems? I will argue that several features make streams a useful model system to gain insight into the decomposition process and associated decomposers, and then highlight examples where studies in streams have advanced general understanding of the system. These include (i) the finding that fungi mediate the control of decomposition rate exerted by litter quality and external nutrient availability, (ii) quantification of the relative roles of bacteria, fungi and detritivores (shredders), (iii) demonstration of the importance of fungal litter decomposers as secondary producers in ecosystems, and (iv) the notion that quantification of decomposition products is important. While many concepts and findings from streams appear to be broadly applicable, several limits to generalization must be recognized. Thus, attention to specific properties of decomposition systems is indicated when translating concepts, observed patterns and discovered mechanisms to other types of ecosystems.