The development of the Industrial Revolution 4.0 has far-reaching effects on all aspects of life, the economy, and society, bringing various growth opportunities for businesses. However, businesses are still hesitant to apply these new technologies. On a research sample from a survey of 396 Vietnamese enterprises, the study uses the SEM-neural network method to determine the relationship and importance of five groups of factors affecting the firms’ Industry 4.0 technologies adoption. The results suggest that five groups of factors, including Perceived characteristics, Technological competencies, CEO characteristics, Environmental characteristics, and Subjective Norms, all positively and significantly impact the Industry 4.0 technologies adoption in Vietnam. In particular, Technological competencies are the most influential factors according to the SEM method, while Subjective norms factors have the most decisive impact according to the neural-network method. Moreover, the research also found that adopting Industry 4.0 technologies depends on different company characteristics, such as age, size, status, and industry.