Government school teachers in India are formally protected under Section 27 of the Right of Children to Free and Compulsory Education (RTE) Act, 2009, which restricts their deployment to non-teaching duties except for decennial census work, disaster relief, and election-related duties. In practice, however, teachers across several states, including Uttar Pradesh, continue to report being pulled into a much wider range of administrative and data-entry tasks, from updating portals such as UDISE Plus and mid-day meal monitoring systems to serving as Booth Level Officers and handling welfare-scheme verification. This study examines the relationship between the administrative workload carried by government secondary school teachers in Uttar Pradesh and their classroom effectiveness, as reported by the teachers themselves and rated by their head teachers. A survey was conducted with 260 government secondary school teachers drawn from three districts of Uttar Pradesh, using a structured Administrative Workload Scale covering data-entry and portal work, election and census duty, mid-day meal and welfare-scheme administration, and miscellaneous clerical tasks, alongside a Classroom Effectiveness Scale covering lesson preparation, student engagement in class, use of teaching aids, and timely completion of syllabus. Results show that a large majority of teachers spend a substantial part of their working day on non-teaching administrative tasks, and that higher administrative workload is significantly and negatively associated with classroom effectiveness (r = -0.41, p < 0.01). Regression analysis confirms that administrative workload remains a significant negative predictor of classroom effectiveness even after controlling for teaching experience and pupil-teacher ratio at the school. The paper situates these findings within the wider national conversation on teacher deployment for non-academic duties and offers concrete, low-cost recommendations for protecting instructional time in Uttar Pradesh’s government schools.