How off‐farm employment can enhance welfare in terms of food consumption and poverty alleviation is a critical question facing many developing countries. This study addressed that question by pursuing two objectives: (i) to quantify the impact of off‐farm employment on rural households’ welfare, food security and poverty; and (ii) to examine the factors that affect their decision to work off‐farm. Using panel data, we estimated a difference‐in‐difference combined with a propensity score matching model. The findings show that off‐farm employment improves income, ensures food security and contributes to poverty alleviation. The results also show that age, marital status, education, labour, financial capital, land, location, market access and losses from natural disasters are significant contributing factors to the decision to participate in off‐farm employment. The findings suggest that to improve the welfare of rural households, the Vietnamese government should proceed with policies that enhance their opportunities for participation in off‐farm employment.