This study examines the factors determining research output in Viet Nam, particularly the publication of Web of Science (WoS) listed journals, which affects the global ranking of Vietnamese universities. We analyzed the academic profiles of 2,042 faculty members from the top 12 universities, as ranked by Webometrics in 2021, using a nonlinear Poisson regression model. The analysis identified eight key factors influencing publication count: age, gender, field of study, academic degree, academic rank, professional title, administrative position, and educational background. Among them, productivity follows an inverted U-shaped pattern with age, increases with a PhD degree and foreign education, and is higher among male researchers and those in natural sciences. In contrast, administrative roles are associated with fewer publications, likely due to shifting priorities and increased non-research responsibilities. The academic rank of associate professors is related to higher research outputs, while the academic rank of full professors and professional titles shows little evidence of correlation to research outputs. The findings emphasize the diverse factors influencing academic research output. Based on these findings, we propose recommendations to boost international publication productivity in Vietnamese universities.