Structural contacts between the Triassic to Cretaceous Mamonia Complex and the Upper Cretaceous Troodos Complex have been examined in southwest Cyprus. The contacts are invariably near vertical in the south of the region, and moderate to high-angle in the north. Field evidence suggests that these two contrasting oceanic basement types were juxtaposed by strike-slip tectonics. During the late Cretaceous, a sinistral strike-slip fault zone was active in the southern area, whilst in the northern area a central block was uplifted at a restraining bend. This model can explain the presence of interleaved tectonic slivers of both Mamonia and Troodos basement and earlier formed metamorphic rocks. It also explains the presence of diapirs of sepentinized harzburgite and dunite along the fault contacts, which originated as deep oceanic fractures. Finally it provides a satisfactory explanation for the origin and distribution of submarine debris flows, only found in the northern area, derived from erosion of a transpressional ‘push-up’ structure. Constraints on the timing of strike-slip faulting suggest that this episode of tectonism in southwest Cyprus is coeval with the 90° anti-clockwise rotation of parts of Cyprus, indicated by palaeomagnetic data. A model is proposed which reconciles anti-clockwise rotation of the Troodos Complex with sinistral strike-slip displacement along its contact with the Mamonia Complex. This model differs significantly from several recently published models which invoke dextral strike-slip along the same contacts associated with anti-clockwise rotation of the Troodos microplate.