Present study is designed to investigate the effects of gender and education level on maximum phonation time. A total of 150 healthy adults aged between 20-35 years, and grouped in three levels of education (primary school, high school and university graduates) were served as participants. Maximum phonation time was measured by sustained vowel /a/ production. Sustained /s/ and /z/ production, and s/z ratio were used for measurement of phonatory and respiratory efficiency. A two way ANOVA was used for statistical analysis. Significant main effects were found for gender and education level for sustained vowel /a/ production. Significant main and interaction effects for gender and education level were found for sustained /s/ and /z/ productions. However neither significant main effects nor interaction effects were found for s/z ratio.