Understanding variations in eruptive style and defining the processes and controls on different eruption styles is particularly important at arc volcanoes. This is due to the range of eruption styles which vary from phreatic behaviour to effusive magma extrusion and large explosive Plinian eruptions. Such eruptions can have wide-ranging and long-term impacts on vulnerable communities living near volcanoes. Magma storage and chemistry are key to understanding the origins of such variations along-arc. The Lesser Antilles Arc provides a perfect setting to investigate magma storage, magma composition and eruptive style variations associated with arc volcanism. This arc is comprised of eleven volcanically active islands. Since 1900, there have been 24 eruptions. Many eruptions have resulted in thousands of deaths, large scale and long-term displacements and severe economic impacts, which have had profound impacts on the people living in this region. Through this review we highlight the variations observed in magma storage, which is described as a vertically extensive trans crustal mush system. We hypothesise that across the arc there are generally three levels of the mush storage system. First, a deep system at 25 km (ca. >400 MPa). This system is poorly constrained and contains the most primitive magmas which fractionate to produce magmas which ascend into the second mid-crustal system at 10–18 km (ca. 320–400 MPa). The mid-crust stores basalt to basaltic andesite which supplies and remobilises the third and last shallow system at <10 km (ca. <200 MPa) which hosts evolved dacitic – rhyolitic magmas. This is the most well-defined part of the magma system and is the region supplying eruptions. The remobilisation of the shallow system and the production of eruptible magma can result in eruption, with magma composition considered a first order control on eruption style. This is observed with the northern and central arcs, which produce evolved compositions, large explosive and dome-forming eruptions, with associated hazards. Magmatic productivity compositional variation and variation in magma storage depth is controlled by the distribution of subducted serpentine. This is particularly important to consider in the central arc which has the highest magma productivity and evolved magmas stored at shallow depths. These magmas are likely to erupt explosively in the near future, given the unrest observed at many systems in the central arc. Despite the fact that advancements in science, technology and our understanding of volcanoes in the arc undoubtedly prevented large numbers of casualties in the late 20th and 21st centuries, large evacuations of people remain unavoidable. In some cases, evacuation becomes long term displacement and results in major socio-economic impacts. This highlights the need for future crises to be effectively managed so as to limit the socio-economic impacts and maintain the relationship between scientists, authorities and the population.