The present study investigates S-palatalisation in urban Scottish speech, focusing on /str/-clusters. The purpose of this study is to give an account of STR-palatalisation and to assess whether the feature has spread into Scottish English, a British variety which is linguistically and geographically furthest from southern English varieties. In doing so it provides evidence for another example of geographical diffusion within dialect levelling and sheds light on its social distribution. Furthermore, the question whether S-palatalisation can appear in clusters containing an alveolar tap or trill type of /r/ may contribute to the discussion surrounding the motivation of the sound change. Finally, it may extend the list of non-local nonstandard variables introduced from England to Scotland, and contributes to filling the lack of research on linguistic variation in Edinburgh. After considering theories of dialect levelling and geographical diffusion, and examples of innovation diffusion in urban Scots, this paper will provide an overview of the few publications that have so far considered STR-palatalisation. Having gained an understanding of the linguistic variable, I will briefly discuss the two variables used in this study: age and social class. After giving a detailed account of the methodology applied, the results of the analyses will be presented and discussed from which some conclusions will be drawn. This study has found that for several speakers in Edinburgh, /s/ in /str/-clusters is statistically significantly [ʃ] or clearly retracted towards [ʃ]. Age and social class both appear to be relevant social factors associated with STR-palatalisation. The data yield apparent-time evidence for STR-palatalisation being a sound change in progress which seems to affect working-class speakers first, but not exclusively. Alveolar forms of /r/ may occasionally cooccur with palatalised /s/, although this is not the norm. Hence, it is likely that the place of articulation in /r/ and /s/ within /str/ is a crucial aspect in the debate about the motivation of the sound change.