This study aims to characterize the readiness of big data adoption and identify important factors for assessing the readiness of Vietnamese SMEs to adopt big data. Consequently, divide SMEs into specific groups based on readiness aspects in order to establish individual group-related recommendations for adopting big data. Questionnaires were used to collect data from 274 SME managers in the manufacturing and service sectors. The key factors defining the readiness of big data application in SMEs were determined by Exploratory Factor Analysis. K-mean clustering analysis was used to group SMEs. The findings highlighted that SMEs are well prepared to adopt big data in decision-making culture, customer interaction, data security, and business strategy factors but not ready in human resources, technology resources, budget resources, government support, and vendor support factors. Big data adoption readiness was defined into three dimensions, namely, Resources, Governance, and Environment readiness. The findings of this study will be important for managers, providers, and policymakers to better understand the factors that assess readiness to adopt big data in SMEs. Hence, they could build effective strategies to incorporate big data and increase their business value and competitiveness.