Previous research on community forestry in Thailand has mainly focused on its institutional dimensions. Comprehensive knowledge on the production of non-timber forest products and on harvesting practices and decision-making processes is therefore still limited, particularly in relation to community-based forestry. A survey was performed to estimate the production of non-timber forest products and to characterize the diversity of harvesting practices and decision-making processes in northern Thailand's community forests. Field investigations were conducted once a month for 12 months in seven community forests in the Lainan sub-district in Nan Province, using a grid-based sampling technique. Production and productivity of the main non-timber forest products were calculated by total fresh weight. In-depth interviews were conducted individually with 231 local harvesters to understand their non-timber forest product harvesting practices and decision-making processes. Young shoots of Melientha suavis, queen broods of Oecophylla smaragdina and edible mushrooms were found to be the three main non-timber forest products collected, with productivity of 2, 12, and 2 kg/ha/year, respectively. Harvesting practices were characterized as applied by (A) landless villagers, (B) small- and medium-sized landholders, (C) larger landholders, and (D) outsiders. Local harvesters displayed different decision-making processes in resource harvesting depending on periods of resource availability, the duration of harvests and the quantities harvested. These quantitative data on resource productivity together with knowledge of harvesting practices and decision-making processes among harvesters will provide input to a participatory resource management process to support exchanges of knowledge among local stakeholders and explore scenarios for appropriate rules of access so as to improve the sustainability of non-timber forest product harvesting.