In Mozambique, weather extremes threaten development progress, while pronounced poverty aggravates the climate vulnerability of the population. With the country being a major recipient of official development assistance, Mozambique’s development strongly depends on donor investments. Against this background, we aim to encourage the mainstreaming of climate adaptation into development assistance. An analysis of donor investments at a sub-national level showed that a significant proportion of development assistance was invested in climate-sensitive sectors in regions highly exposed to extreme weather conditions. Major damage caused by weather extremes motivates a stronger integration of climate policies into development assistance. Although Mozambique has a supportive legislative environment and climate awareness among donors was found to be high, the limited institutional capacity restricted mainstreaming initiatives. Given major barriers at the national level, bilateral and multilateral donors are able to play a key role in fostering mainstreaming in Mozambique.