In this study, it was aimed to examine the quality of service expected and perceived by the customers of private gyms in terms of some demographic variables. The research was designed in the survey model, which is one of the quantitative research methods. A total of 1150 individuals selected with the convenience sampling method participated in the study. Service Quality Assessment Scale (Gürbüz, Koçak, & Lam, 2005) was used as the data collection tool. The measurement tool consists of 34 items and 4 sub-dimensions. SPSS package program was used in statistical analysis. In the normality test of the data, Kolmogorov-Smirnov test values were taken into consideration, and it was determined that the data did not show normal distribution. In the analysis of the data, Mann-Whitney U, Kruskal Wallis H, and Spearman Correlation tests were used. Research findings showed that the Expected Service Quality Scale had the highest average value for the Personnel (x̄=6.29±.865) sub-dimension and the lowest average value for the facility (x̄=5.96± 1.041) sub-dimension. On the other hand, in the Perceived Quality of Service scale, while the facility (x̄=4.90±1.301) sub-dimension had the highest average, the program (x̄=4.75±1.459) sub-dimension had the lowest average value. In terms of marital status variable, significant differences were found only in favor of the married group in the expected service quality scale. Besides, significant differentiation was observed in the sub-dimensions of the expected service quality scale according to the occupational groups. In the correlation analysis results, significant relationships were observed in the Expected Service Quality and perceived service quality scale sub-dimensions. As a result, service quality can be considered one of the factors that customers attach importance to their business preferences, and that is effective in providing satisfaction. Also, the research results showed that demographic variables such as marital status and occupational groups could affect the expected and perceived service quality. Substances were not affected by age, marital status, department, average income, and class status.