Sorghum and pearl millet production has been very low in most parts of the world with only few countries growing these under commercial production. In arid and semi-arid areas, sorghum and pearl millet are the best to adopt as they are drought-tolerant and perform better under harsh conditions. Many farmers in semi-arid areas of Zimbabwe who grow sorghum and pearl millet realize grain yield ranging from 200 to 400 kg ha−1. The main objective of the study was to determine the effects of rainwater harvesting and mulching on sorghum, pearl millet yields, and rainwater use efficiency in semi-arid areas of Zimbabwe. The experiment was laid in a randomized complete block design during the 2022/23 and 2023/24 cropping seasons. Three rainwater harvesting techniques (tied ridge, planting, and infiltration pits) were used as a main factor, and three mulching types (5 t ha−1 legume straw, 5 t ha−1 maize straw, and no mulching) were used as a subplot factor. Slope was used as a blocking factor. Data collected was based on panicle length, grain yield and water use efficiency of sorghum and pearl millet. Interactive effects of planting pit, legume straw mulching and 2023/24 were significant (p ≤ 0.05) and had the highest panicle length of 18.7 cm and 19.2 cm for sorghum and pearl millet respectively. The use of rainwater harvesting and mulching showed a significant increase in grain yield (p ≤ 0.05). Highest sorghum and pearl millet grain yield of 1410.3 kg ha−1 and 1210.1 kg ha−1 was observed from planting pit +5 t ha−1 legume straw mulching respectively. Rainwater use efficiency was significant with sorghum having a 3.35 kg mm−1 ha−1 under planting pit +5 t ha−1 legume straw mulching in the 2022/23 season. It can be concluded that the integration of mulching and rainwater harvesting has the potential to mitigate climate change and increase food production in semi-arid areas.