<p>The use of tropical peatlands as the last frontier for oil palm expansion raises environmental and socio-economic concerns. In response, alternative cropping systems, such as oil palm agroforestry, have emerged as a more diversified approach that integrates various crops within oil palm plots. This system has the potential to mitigate both the environmental and economic risks associated with monoculture oil palm cultivation on peatlands. This study uses a case study approach to explore the factors influencing smallholder decisions to diversify oil palm cultivation in privately owned peatlands in West Kalimantan, Indonesia. Using a mixed-method approach combining questionnaires and semi-structured interviews, we identified key positive and negative factors influencing smallholder decision to diversify oil palm plots located in peatland area on private land. Our results indicate that 41.67% of smallholders surveyed are currently practicing oil palm agroforestry. Meanwhile 51.67% express interest in practicing agroforestry or continue with their agroforestry plots. We categorized the influencing factors into four main groups: agronomic, institutional, socio-economic, and biophysical. We also found that smallholders practicing oil palm agroforestry tend to have lower total incomes but benefit from greater flexibility due to enhanced food security provided by a greater diversity of crops cultivated for self-consumption and market revenues. These results exemplify that factors associated with diversification are not a singular, uniform process but a dynamic interplay between global and local socio-ecological contexts.</p>