Pegged on Protection Motivation Theory, a modified socio-cognitive model of private adaptation to climate change and variability was deployed in order to provide a better understanding of the determinants of small-scale farmers' adaptation intent and adoption of adaptation strategies in semi-arid lowlands of Mwanga District. In this regard, adaptation was conceptualized as a two-step process encompassing farmers' perceptions that climate was changing and farmers' response to changes. Basing on a pragmatic philosophy, a cross-sectional sequential explanatory mixed methods research design was deployed. During the first step-process, categorical data were collected through administration of a closed-ended survey questionnaire to 328 household heads. Binary and proportional odds logistic regressions were run through IBM SPSS (Version 20) in order to analyze categorical data for testing nine (9) null hypotheses. Statistically significant results were established when p values were < 0.05 at 95% confidence intervals. During the second step-process, qualitative data were generated through focus group discussions with 30 participants, in-depth interviews with 16 key informants, and participant observations and subjected to iterative thematic content analysis. The findings revealed that income, village's geographical location, farming system, membership to farmer-based group, competitive price for produce, credit, age, education, and extension service positively influenced farmers' adoption of adaptation strategies while workforce and perceived risk of rain on crop yields negatively influenced farmers' adoption of adaptation strategies. Thus, it was concluded that farmers' adaptation intent and adoption of adaptation strategies in the study area were largely explained by objective adaptive capacity rather than cognitive factors.