Open Innovation (OI) has been studied mainly in large-scaled high-tech firms or Multinational Corporations (MNCs). Few have studied OI on small and medium-sized enterprises (SMEs). Since SMEs make vital contributions to national and global economics and innovations, their engagement in the OI should not be neglected. In addition, the demand to access supporting resources, especially knowledge, from open communities is critical for SMEs, through a backward knowledge flowing process called reverse knowledge sharing. This study investigates on the relationship among OI, reverse knowledge sharing and SME performance with questionnaire data collected from SMEs in Vietnam. Results indicated that there was a positive relationship between OI and reverse knowledge sharing. Results also indicated that the degree of relationship between SMEs and their stakeholders moderated the relationship between OI and reverse knowledge sharing. Practical implications and theoretical potential for future research are discussed.