Despite rapid economic development in South-East Asia in the past decades there is still great economic heterogeneity between Cambodia, Laos, Thailand, and Vietnam. A welfare gap exists between urban populations and parts of the rural population who remain dependent on agriculture and natural resource extraction. Changes in the environment, namely environmental resource degradation and climate change, can expose their livelihoods to severe pressure, including incidences of food insecurity. At the same time, the spread of modern technology in the form of smartphones and access to the internet opens up reams of opportunities to rural households to improve their income-earning portfolio. Focusing at the household level, this dissertation identifies how these processes affect rural households in Cambodia, Laos, Thailand and Vietnam based on their livelihood strategies in six different essays. It uses these findings to generate ideas how rural livelihoods could be transformed and how development policies could be adjusted so that in the future more households will benefit from the rapid economic development in South-East Asia and avoid to be negatively affected by its external effects.