<p>Studies on flood risks considering combined changes in land use and land cover (LULC), climate, and socioeconomics are scarce. This study assesses the flood risks in an urbanizing floodplain adjoining the megacity Dhaka, Bangladesh, considering all these changes. Suitable, locally-fit indicators are used to assess the risk components—hazard, exposure and vulnerability. As hazard indicators, flood depth, land slope, distance from river, and drainage density are used. A good quality local DEM along with frequency analysis of river flood levels is used to derive the hazard indicators. No. of people, no. of households, and cropped area are used as exposure indicators. Future projections of these indicators are made with logistic growth model and trend analysis. Sensitivity and lack of capacity are considered multiplicative components of vulnerability. As sensitivity indicators, total-population density, female-population density, dependent population, disabled population, LULC, and distance to main road are considered, and as adaptive capacity indicators, employment rate, literacy rate, length of paved roads per 10,000 people, proportion of people availing tap water, proportion of people accessing sanitary toilets, no. of school-cum-shelters per 10,000 people, and no. of health personnel per 10,000 people are considered. These indicators are also projected for the future. LULC is projected with the Cellular Automata-Markov chain algorithm in the Google Earth Engine platform, and hydrological impact of climate change is evaluated with a two-dimensional hydrodynamic model simulation. The indicators are combined using weighted-additive equations to derive the risk components. Analytic hierarchy process is used to combine the relevant indicators into their respective risk components through key informant interviews. The results indicate that urban areas can increase by 45%, flood level by 0.38&#xa0;m, and very high-flood areas by 37% in 2050. Combined impacts of LULC, climate, and socioeconomic changes indicate that the rapidly urbanizing areas of the floodplain could face an increasing flood risk till 2050 due to mainly increasing sensitivity, while the areas already highly urbanized could experience slightly less risk due to mainly improving capacity. The contribution of socioeconomic indicators to flood exposure and sensitivity is found to be more (79–81%) than the biophysical indicators (19–21%). Similarly, the contribution of socioeconomic indicators to adaptive capacity (66.5%) is more than the physical indicators (33.5%). All LULC classes contribute to sensitivity, however urban and agricultural classes contribute more. The study provides important insights on spatial and temporal variations of flood risks in an urbanizing floodplain close to a megacity and would be useful for flood policymakers and urban planners for urbanizing floodplains in Bangladesh and elsewhere.</p>