This paper has two main objectives: (a) to put the vast body of research on Swedish as a second language (SSL) into one coherent framework; and (b) to test the predictions deriving from processability theory (Pienemann, 1998a, 1998b) for Swedish against this empirical database. We will survey the 14 most prominent research projects on SSL covering wide areas of syntax and morphology in longitudinal and cross-sectional studies. This survey is the first to be carried out for Swedish, and it will bring the body of two decades of research into one unified framework. We proceed in the following steps: First, a brief summary of processability theory is given. Then the theory is used to generate a unifying framework for the development of the specific L2 grammatical system (Swedish). Finally, the new framework is tested in the above-mentioned empirical studies.