Access to safe and adequate sanitation remains a significant challenge in arid and semi-arid areas. To address this issue, onsite sanitation facilities have gained global acceptance, where financial constraints often hinder the installation of conventional centralized systems. However, studies have observed that faecal matter accumulating in these technologies is usually poorly managed, posing risks to public and environmental health and leading to adverse economic and social effects. The study investigated the influence of social, environmental, and technological factors on the management of faecal matter in Isiolo Sub County. A convergent mixed methods design was used to obtain quantitative data using structured questionnaires and qualitative data from two focus group discussions. Stratified and proportionate random sampling techniques were used to select households, while purposive sampling was applied for informants. Quantitative data were analyzed using Statistical Package for Social Science (SPSS) version 26.0 for descriptive statistics and logistic regression analysis. Logistic regression was computed in univariable and multivariable analysis to determine the relationship between predictors and dependent variables, and results were presented as an odds ratio with 95% Confidence Interval (CI). Qualitative data were analyzed thematically and presented in narratives. From the findings, the pit latrine was most commonly used at 77.1%, and about 46.5% of the resulting excreta was poorly managed. The study established social factors such as secondary education (AOR = 4.085, p < .001); gender roles (AOR = 0.518, p = 0.028), knowledge of safe disposal (AOR = 22.50, p < .001), and social norms (AOR = 0.347, p = .001) to have a significant influence on the management of faecal matter. Environmental factors such as rainfall (AOR= 0.825, p = 0.0315), space availability (AOR = 0.89, p = .036), and land use (AOR=1.012, p=0.013), along with technological aspects like sustainable toilet (AOR= 1.398, p=0.036); latrine accessibility (AOR= 0.783, p=0.05); local resources (AOR = 1.488, p = 0.009) were also statistically associated with effective faecal matter management. The study concludes that social, environmental, and technological interaction influences faecal matter management in arid and semi-arid areas. The study recommends that policy makers and sanitation stakeholders, such as the county Government, promote public education and community awareness, promote resilient and lined sanitation technology, strengthen local capabilities through intra-community skilled labour training, and incorporate land experimentation with usability into infrastructure development. To promote sustainable and inclusive faecal matter management, it is vital that sanitation policies across the affected realms can adapt accordingly to context, particularly in disadvantaged arid and semi-arid lands (ASAL)