Geologic thinking about the Svalbard Caledonides has long been shaped by the hypothesis that large‐scale strike‐slip plate motions assembled the archipelago in mid‐Paleozoic time. However, the first detailed studies of upper Proterozoic meta‐sedimentary rocks along one of the postulated strike‐slip zones, in northern Wedel Jarlsberg Land, southwest Spitsbergen, have produced no evidence for major Caledonian transcurrent shear in the region. An angular unconformity divides the greenschist‐facies rocks into two sequences and chronicles a period of intense deformation in late (?) Proterozoic time. Rocks above the unconformity (conglomerates, dolomites, greenschists, and Vendian diamictites) provide a detailed record of early to mid‐Paleozoic deformation. The widely distributed conglomerates allow definition of regional strain patterns and construction of a possible deformation path for the study area. Deformed conglomerate clasts range from oblate and parallel with bedding, to prolate and aligned parallel to the axes of northwest trending folds. Microstructural evidence indicates that net orogen‐parallel elongation of clasts resulted from modification of an early subhorizontal flattening fabric by later progressive coaxial flattening in a vertical plane. This is consistent with macroscopic evidence for two distinct, though perhaps regionally diachronous, phases of deformation: a period of ductile thrusting and recumbent folding followed by upright to northeast vergent folding, in a progressive trend toward more brittle behavior. The structural fabric of the rocks may record their incorporation into an accretionary prism, in a process closely linked with blueschist emplacement in central west Spitsbergen. The rocks provide no evidence for vorticity about a vertical axis, as might be expected near a major strike‐slip zone. Stratigraphic correlation of Proterozoic rocks on both sides of the postulated fault zone also argues against large‐scale strike‐slip displacement during Caledonian deformation in southwest Spitsbergen. The results of this study and others call for critical reexamination of the prevailing tectonic model for Caledonian Svalbard.