Meetings are the primary communicative practice in every organization in order to fulfill the vital consensus, make changes and exchange ideas. Much time and effort are devoted to meetings aiming at information sharing, decision making, and problem solving. Therefore, finding out how voice and leadership power affect meeting effectiveness becomes essential, especially in Vietnamese organizations. First, the paper reviews factors affecting meeting effectiveness including leadership, agenda, substantive conflicts and internal communication. Next, a structured questionnaire was completed by a sample of 157 participants who are working at 31 Vietnamese organizations from a variety of sectors such as tax, banking, health service, airlines, education and business. Finally, the results reveal two antecedents affecting meeting effectiveness: Leadership and Substantive conflict. Leaders play the vital role in formulating an organization vision, making effective plans for vision implementation in reality as well as creating a healthy environment and organizational culture to grow ethical behaviors inside the organization. Their subordinates surely become more committed to the organization when they are working with inspirational leaders who willingly instruct them in uncertainty and encourage their abilities and talents. In addition, it is obvious that during the process of interaction, conflicts may exist and therefore how to resolve conflicts needs to be concerned. At any circumstances, most authors from previous studies believe that when conflicts occur in the meeting, if they are resolved in a constructive way, they will surely bring more benefits for the organizations