The projected widening and weakening of the Hadley circulation hold large societal impacts at low and subtropical latitudes. Previous studies suggested that ocean heat transport (OHT) might play a central role in future circulation's changes. Here, using ensembles of model integrations, we quantify the role of OHT in the evolution of the Hadley cell over the 20th and 21st centuries. We find that by the end of the current century OHT reduces the widening of the circulation by ∼35% (0.42°) and its weakening by ∼60% (1.3 × 1010 kg s−1). As a result, OHT delays the emergence from internal variability of the widening by 30 years and of the weakening by 20 years. Lastly, while oceanic heat uptake accounts for most of the reduced widening, and thus merely delays it by reducing surface warming, horizontal heat transport and net heat uptake have comparable impacts to reduce the weakening of the circulation. Key Points By the end of the 21st century ocean heat transport is projected to reduce the widening of the Hadley cell by ∼35% and its weakening by ∼60% The reduced widening is mostly due to the increase in oceanic heat uptake, which thus delays the expansion of the tropics Horizontal heat distribution and net heat uptake are both responsible for weakening the circulation by redistributing latent heating