Background Leaf spot disease of Telfairia occidentalis, caused by Phoma sorghina, represents one of the major biotic constraints to T. occidentalis production under small scale farming systems in West Africa including Cameroon. Currently this critically important seed and leaf vegetable is cultivated under varying altitudinal levels at different planting dates. In this framework, a field study was conducted in 2019 and 2020 cropping seasons between March and July in the localities of Dschang and Santchou to determine the influence of altitude and planting date on the prevalence and severity the disease. Material and methods A 2 by 4 factorial randomized complete block design (RCBD) with three replications and four planting dates were used. Data for disease prevalence and severity documented fortnightly, were submitted to general linear model for analysis using SPSS version 23, and the means were separated by least significant difference (LSD) at a 95% confidence interval. Results Statistical analysis revealed that, the low altitude recorded a significantly (p < 0.05) lower prevalence than high altitude while disease severities between both altitudes were not significantly different. Moreover, the initial three planting dates at low altitude and planting date three in Dschang recorded significantly lower prevalence than other planting dates investigated in the study. Conclusion We established that, the initial three planting dates at low altitude and planting date three at high altitude could be helpful in reducing leaf spot prevalence and severity of T. occidentalis.