The oil palm industry is vital in food and energy production and significantly contributes to the Thai economy. Nevertheless, the sector faces environmental management challenges, especially waste management. With an awareness of the importance of a circular economy, this study aims to utilise the material circularity indicator (MCI) to measure the material circularity in multiple products of the Thai oil palm industry and plan for sustainable improvement. The circularity measurement result shows that palm oil production is more circular than linear, with a calculated MCI of 0.5372. This shows the importance of recycling, reusing, and composting of co-products, residual oil, and wastes of oil palms to achieve the sustainable development of Thai agriculture. The results also show that the MCI value may be enhanced by increasing the biomass’s oil extraction rate (OER) and calorific value. By improving the OER from 18% to 23%, the MCI value rises to 0.6230, explaining a better circularity of the oil palm industry. The oil palm industry, the government, and related authorities may use the study results to plan for the palm oil process improvement to enhance the circularity in the long term. The study has a limitation: The data used in the analysis are from a limited number of palm oil factories. An increasing number of participating factories may enhance the study results.