This study was carried out to determine the relationships between supervision and teachers' performance and attitude in secondary schools in Kuala Lumpur, Malaysia. This is a quantitative study where the 5-point Likert-type-scale questionnaire was used to analyze data using descriptive and inferential statistics. Simple random sampling was used to select the respondents. This study entailed respondents from various schools in one of the districts in Kuala Lumpur which comprises 200 teachers and 50 supervisors. Descriptive statistics were used to describe the status of supervision practices, teachers' attitude toward supervision, and teachers' level of performance after supervision. Multiple regression analysis was used to test the relationships between supervision (supervisory practices--directive, collaborative, and nondirective approach) and teachers' performance and attitude. The current status of supervisory practices, teachers' attitude toward supervision, and teachers' performance after supervision is found at moderate level in secondary schools in Malaysia. As a whole, supervisory practices are not correlated with teachers' performance and attitude. But worthy to mention, directive supervision is positively and significantly related to teachers' performance and attitude. This study result will benefit the policy makers, school supervisors and headmasters to choose the right kind of supervisory practices which can contribute to better teaching performance.