This review is an updated synthesis of the late Neoproterozoic to Terreneuvian arc magmatism, arc accretion, backarc crustal extension and oceanic basin development along the northwestern Gondwana margin, which included northern Africa and the Avalonian-Cadomian domains of North America and Europe. Two accretionary orogens, partly contemporary with the Pan-African Orogeny, are described here. The Cadomian orogen includes several arc systems developed on ancient (ca. 2.7 and 1.9 Ga) crust, which remained attached to Gondwana after the Cambrian rift and Ordovician opening of the Rheic ocean. The Avalonian orogen comprises an arc system developed on juvenile crust (ca. 1.3–1.0 Ga), which originated within the Panthalassa-like Mirovoi Ocean surrounding Rodinia, and formed the basement of younger ‘peri-Gondwanan terranes’ that subsequently drifted from Gondwana. The Avalonian and Cadomian orogens may have been adjacent to one another forming an arc‒backarc system wrapping the Panthalassan side of northwestern Gondwana. Although the stratigraphic and magmatic proxies of these orogenic belts are relatively well established, remaining challenges that geoscientists will face are complex and interconnected, requiring holistic solutions that should include: (i) better quality of palaeomagnetic data, (ii) an improved understanding of the precise location and extent of the Clymene Ocean that may have separated Amazonia (and Avalonia) from West Africa (and Cadomia) across the Ediacaran‒Cambrian transition, and (iii) the necessity of finding robust craton-discriminating criteria distinct from the statistical analyses of detrital zircon spectra, which have recently questioned the lack of Mesoproterozoic detrital zircon populations (‘Mesoproterozoic gap’ paradigm) as a hallmark of the West African craton.