The aim of this study was to investigate the morphosyntactic development of Grundvux learners (adult learners who study school subjects at elementary school levels in Sweden) of English with the aid of Processability theory, or PT, and to investigate the potential influence of exposure to English outside school and the participants' highest completed formal education on the participants' morphosyntactic levels. The participants of this study were Grundvux learners who studied English either on National Course 2, 3, or 4. This study also investigated how similar or different Course 2, 3 and 4 participants were when it comes to their highest attained PT-levels. The participants described a picture series and answered questions about their highest completed education from their home countries and how much they tend to be exposed to English on a weekly basis outside school. The results show that Course 2, 3 and 4 participants have both similarities and differences regarding their highest attained PT-levels. The results also show that there could be a possible connection between educational background and morphosyntactic development, i.e. that educational background can have a solid influence on morphosyntactic development. Furthermore, this study shows that a connection between exposure to English outisde school and morphosyntactic development is not likely. Yet, more research with more participants and tasks with different instructions are needed to draw definitie conclusions about the effects of exposure to English outside school and highest completed education on learners' morphosyntactic development. Lastly, this study provides some information to in-service teachers about what morphosyntactic structures to teach and when based on the learners' highest attained PT-levels.