This study attempts to investigate the awareness of SMEs in some northern provinces of Vietnam about online marketing, to determine the factors encouraging the SMEs to use online marketing channels, and to measure to what extent they influence the adoption. The quantitative method measures the intensity relationship between determinants in the Technology, Organization, and Environment (TOE) based theoretical model. In combination with it, the qualitative method is applied for the first phase of research exploration. Relying on the research model, a questionnaire is designed to survey 234 SMEs in some northern provinces of Vietnam. Multivariate regression is run with the help of software SPSS 22 to test which factors influence the adoption of online marketing. The result indicates that all three factors of the technological, organizational, and environmental context are drivers of online marketing for SMEs in some northern provinces of Vietnam. However, the organizational factor is the most important one. Based on these important results, the study proposes implications for SMEs to improve their marketing activities.