E-commerce has transformed the entire process of product sales between sellers and buyers, which has been of economic benefit for both parties. The purpose of this paper is to analyze the main decisive factors of this adoption, integrating aspects of Rogers' Innovation Diffusion Theory (IDT), the Technology-Organization-Environment (TOE) model, and the Technology Acceptance Model (TAM). Through a quantitative method, data was collected and analyzed from 434 SMEs using a questionnaire. Findings highlight that the perceived ease and usefulness of e-commerce, influenced by perceived advantage and observability, are critical determinants in the decision to adopt these technologies. Additionally, it was found that management support and employees' knowledge of Information Technologies (IT) play a relevant role in this adoption. This study adds to the existing literature on technological adoption in SMEs, showing important insights for the northeastern region of Mexico and suggesting avenues for future research. The results are relevant for business decision-makers and public policy formulators, offering guidance on how to enhance e-commerce adoption in the SME context.