Livelihoods of communities living in mountain areas is typically dependent on subsistence agriculture and smallholder farming. The needs of smallholder rural mountain farmers for livelihoods cannot be addressed without providing them alternative income within available resources. Beekeeping has proven to be such an alternative livelihood option with potential of providing alternative income security to smallholder farmers living in rural mountain areas.However, how successful and sustainable beekeeping interventions are in terms of presenting a reliable alternative livelihood option particularly in rural mountain context of Pakistan is less explored. In this context, an impact assessment approach has been used in an ex-post scenario to better understand impacts attributable to an intervention.Applying such approaches in ex-post scenarios help better understand relevance, effectiveness, and suitability and sustainability aspects of interventions. This paper assesses impact of beekeeping pilot intervention on the household income of rural poor living in mountain areas of Pakistan and looks into suitability and sustainability aspects of the intervention in the ex-post scenario. Using ‘Difference-in-Difference’ approach, impact and sustainability of pilot intervention was assessed 4 years after conclusionof the intervention. Findings of the study suggest that average income of beneficiary households from beekeeping is increased by51.54% compared to the average income of beneficiary households assessed at the end of the pilot intervention. Study concludes that interventions on strengthening alternative income security optionsin rural mountain context are sustainable given that the alternative livelihood options are carefully identified and implemented in a participatory manner.