The Qu¿bec Appalachians have been shaped by two major orogenies: the Middle to Late Ordovician Taconian and the Middle Devonian Acadian. Thrust faults and nappe structures characterized the Taconian deformation throughout the Qu¿bec Appalachians, whereas structural styles pertaining to the Acadian orogeny differ from southern Qu¿bec to the Gasp¿ Peninsula. Structural analysis of Late Ordovician to Middle Devonian supracrustal rocks shows two different Acadian deformational regimes: strike-slip tectonics in the Gasp¿ Peninsula and thrust or dip-slip tectonics in southern Qu¿bec. In southern Qu¿bec, Acadian regional deformation produced folds which vary from upright to overturned and tight to isoclinal from the NW to the SE. Major faults (e.g., La Guadeloupe) are northwestward directed thrust faults marked by highly ductile shear zones outlined by mylonite. In the Gasp¿ Peninsula, structural trend is NE and major E-W dextral strike-slip faults transect this trend. Folds are open and upright, inclined and tighter near the major faults where they have a clockwise rotation like the regional cleavage. Major faults (e.g., Grand Pabos) follow corridors delimiting high-strain zones where the fabrics developed are indicative of a ductile-brittle regime of deformation. In the T¿miscouata region, major structural features of both southern Qu¿bec and the Gasp¿ Peninsula are recognized. Structures of this region consist of ENE trending dextral strike-slip faults and high-angle WNW verging reverse faults, parallel to major NNE folds. These structures reflect the transition from purely horizontal movement along major strike-slip faults of the Gasp¿ Peninsula to vertical movement along thrust faults in southern Qu¿bec. Acadian structural variations within the Qu¿bec Appalachians are interpreted in terms of a continental collision of Gondwana along the irregular margin of Laurentian and its Taconian accreted terranes. ¿ American Geophysical Union 1995