Indonesia has a hot and humid topical climate throughout the year. Most people rely on natural ventilation or mechanical fans to reduce heat stress at home because they cannot afford air conditioning. Ensuring thermal comfort conditions for the low-income people living in naturally ventilated dwellings in Indonesia presents an important but challenging task. This research explores the use of passive design strategies for indoor thermal comfort in kampungs, a low-income housing group in Indonesia. To evaluate the impact of passive design strategies, a prototype is developed to represent the typical design, construction, and operation of kampung houses. The architectural design and construction characteristics are mostly based on the guidelines published by the Indonesian government. The kampung prototype has one floor with a total floor area of 35.5 m2. It has a metal-gable attic roof, brick walls, concrete floor, and single-pane and wood-frame windows. The impact of eight passive design strategies, including natural ventilation, insulation, cool roof, cool exterior walls, glazing systems, external shading devices, roof thermal mass, and green walls, are evaluated using EnergyPlus, a state-of-the-art whole building simulation program. These strategies are evaluated individually and in a combination of highly effective ones. The results show that effective natural ventilation is a key strategy for thermal comfort. By increasing the natural ventilation rate from 1 air changes per hour (ACH) to 11 ACH, the number of hours not meeting thermal comfort per ASHRAE Standard 55 is decreased by 32%. Cool roof, cool exterior walls, and green walls are all effective strategies. Using any one of the above three strategies can reduce the number of unmet hours by more than 10%, for a minimum 3 ACH ventilation rate. The impact of wall insulation on indoor thermal comfort is found to be related to the ventilation rate. At lower ACH rates (ACH≤3), adding wall insulation has a negative impact on thermal comfort. However, at ventilation rates higher than 3 ACH, adding wall insulation may improve thermal comfort but the impact of adding wall insulation beyond R-2 is negligible. Roof or ceiling insulation, roof thermal mass, window overhangs, and double-pane windows have almost no impact on thermal comfort. By combining the strategies of full-day natural ventilation (ACH=11 or higher), cool roof, cool exterior walls, R-2 wall insulation and single-pane reflective glazing, the package can reduce the number of unmet hours by 58% as per ASHRAE Standard 55 Adaptive thermal comfort model and by 80% according to a thermal comfort model developed for the Southeast Asian countries, relative to the base case prototype with 1 ACH ventilation rate. The findings of this research work have the potential to contribute to the development of passive house standards aimed at improving living conditions in Indonesia.Considering the projection of increased use of air conditioners in residential buildings including kampungs due to Indonesia’s economic growth and rising living standard, the impact of passive design strategies on energy efficiency is also investigated. An effective package of energy efficiency strategies was developed to achieve maximum reduction in cooling load. It was found that the package of strategies that improves energy efficiency does not necessarily enhance thermal comfort in naturally ventilated kampungs.