Abstract :
The very rapid development of education in Indonesia is an interesting phenomenon to observe, especially with the presence of various private foundations that have contributed to the progress of Indonesian education. One of the private foundations that has demonstrated progress in the field of education is the Lazaris Surabaya Foundation which oversees several schools such as St Louis 1 Catholic High School and St Louis 2 Catholic High School Surabaya. The aim of this research is to find out whether organizational culture, work discipline, work environment and leadership style influence teacher performance at the Lazaris Surabaya Foundation. The data analysis technique in this research is using a validity test, the results of which are declared valid because all calculated r values in this research are > from the r table. The results of the reliability test show that all variables have Cronbach's Alpha > 0.60 so it is stated that all variables research is reliable or consistent. The classic assumption test consists of 3 (three) tests, namely the normality test whose results show that the variables X1, which states that this regression model does not experience multicollinearity or non-multicollinearity, and the heteroscedasticity test which shows that this regression model does not experience symptoms of heteroscedasticity. The results of the multiple linear regression test are Y = 1.585 + 0.092 X1 + 0.261 X2 + 0.080 X3 + 0.269 X4. The coefficient of determination in this study shows that the adjusted R square value is 0.733 or 73.3%, which means that the independent variable in this study makes a high contribution to the dependent variable. The t test in this study resulted in the organizational culture variable (X1) having a calculated t value of 0.795 < t table 1.98580 with a sig value. amounting to 0.492 < 0.05, which means it has no significant effect on teacher performance at the Lazaris Surabaya Foundation, the discipline variable (X2) has a calculated t value of 2.040 > t table 1.98580 with a sig value. amounting to 0.044 < 0.05, which means that work discipline influences teacher performance at the Lazaris Surabaya Foundation, the work environment variable (X3) has a calculated t value of 1.248 < t table 1.98580 with a sig value. amounting to 0.215 > 0.05, which means the work environment has no effect on teacher performance variables at the Lazaris Surabaya Foundation, the leadership style variable (X4) has a calculated t value of 3.905 > t table 1.98525 with a sig value. 000 < 0.05, which means that leadership style has a significant effect on teacher performance at the Lazaris Surabaya Foundation.