The development of Malawian smallholder agriculture has since the 1980s gone through many challenges and there are fears that this may have been a precursor to unsustainable agricultural intensification and worsening poverty. In this paper, we conduct an empirical assessment of smallholder technical efficiency and its determinants using farm household and plot data. We use a non-parametric frontier analysis to analyze the technical efficiency of farmers in the maize-based mixed farming systems. In addition, we use a regression-based estimation to assess the socio-economic and policy related factors that may explain the estimated levels of technical efficiency. The results indicate low to medium levels of technical efficiency, depending on crop variety and soil fertility management option used. Higher levels of relative technical efficiency are obtained when farmers use integrated soil fertility options compared to the use of inorganic fertilizer only. Of the policy variables included in the analysis, agricultural input and output market, credit and extension access strongly influence smallholder technical efficiency. Government needs to resuscitate these public policy issues in order to effectively address sustainability of Malawian agriculture and its impact on poverty.