The objective of this research was to study the factors influencing the ERP: SAP implementation in Thailand for planning and managing an ERP project. The sample was the staff of 127 companies that have been implemented the ERP: SAP in Thailand. The research tool was a questionnaire. Data were analyzed and presented in the forms of percentages, means, and standard deviations. The hypotheses were tested using the logistic regression analysis at the statistical significance level of .05. The study found that the factors influencing the ERP: SAP implementation were correlated with behavioral intention of ERP: SAP system: performance expectance, effort expectance, attitude toward the technology, self-efficacy, anxiety, and communication. Behavioral intention of ERP: SAP system was no correlated with the use behavior of ERP: SAP system. For successful implementation, Therefore, project managers should recognize these factors while planning and designing the ERP projects.