We develop a Socioeconomic Vulnerability Index (SeVI) for climate change affected communities in seven unions1 of Koyra upazilla 2 in south-western coastal Bangladesh. We survey 60 households from each union to collect data on various vulnerability domains and socioeconomic indicators. The SeVI aggregate these collected data using a composite indicator index, where a relative weight is assigned to each indicator with a view of obtaining weighted average index scores for different vulnerability domains in different unions. Results suggest that southern and south-eastern unions are relatively more vulnerable, which are the most exposed to natural hazards and mostly surrounded by the mangrove forest Sundarbans. Furthermore, social, economic and disaster frequency are found as more influential indicators to adaptive capacity, sensitivity and exposure respectively in Koyra. This pragmatic approach is useful to figure out and monitor socioeconomic vulnerability and/or assess potential adaptation-policy effectiveness in data scarce regions by incorporating scenarios into the SeVI for baseline comparison.