This study assessed teachers' understanding about the nature of scientific inquiry (NOSI) and whether this understanding was reflected in their students' responses. The data were collected through the 'Views About Scientific Inquiry' (VASI) questionnaire, a reliable tool for assessing understanding about the NOSI. The sample included science teachers and students of grade X purposively selected from five 'schools affiliated with the local board' (SALB) and five 'schools affiliated with the international board' (SAIB) for external examinations in Pakistan. The responses on the VASI were graded for quality to find the means, frequency count, percentage, and t-test values. The findings revealed no significant difference in teachers' understanding of scientific inquiry (SI) in both school systems. Generally, the teachers had informed views while students held naïve views. The VASI also identified participants' understanding on eight aspects of SI. The SAIB teachers understanding of SI was reflected in their students' responses in some aspects of SI, unlike the SALB teachers. The study recommends incorporating NOSI aspects in teacher education programs and helping science teachers integrate NOSI aspects in their science instruction.