This paper presents an experimental investigation of durational variation in lexical and post-lexical geminate alveolar laterals, under different stress conditions, in Cypriot Greek. Lexical geminates are found to be longer than post-lexicals, and both geminates and non-geminates are longer in word-initial position. The durational distinction is robust in all conditions, but particularly for word-initial lexical geminates. Post-lexical geminates and word-initial lexical geminates are significantly longer when pre-stress. Word-initial geminates are longer when preceded by a word-final nasal (the condition for post-lexical gemination), thus creating a kind of 'supergeminate' consonant and indicating that word-final nasals are not deleted, as has previously been thought to be the case. Implications for the phonological analysis of Cypriot Greek geminates and the role of prosodic and phonotactic restrictions are considered.