BACKGROUND: Low and middle-income countries (LMICs) lack trained child mental health professionals. While teachers' child development experience potentially positions them to fill the gap as lay mental health counselors, they have rarely delivered indicated child mental health care in LMICs. As part of assessing the feasibility of teachers serving as lay counselors, we explored teachers' perceptions of serving as lay counselors and their mental health attitudes and knowledge. METHODS: In 2018, with training and supervision, 19 primary school teachers from five rural, low cost private schools in Darjeeling, India, served as lay counselors in their classrooms. Using mixed methods, we examined teacher perceptions of serving as lay counselor and mental health attitudes and knowledge through a survey (n = 15), a summative assessment (n = 14), and semi-structured interviews (n = 17). For the survey and summative assessment, pre-training, post-training, and post-intervention mean scores were compared using paired t tests. Post-intervention interviews were coded for teachers' perceptions of serving as lay counselor and mental health attitudes and knowledge. RESULTS: Qualitatively, teachers expressed being willing to serve as lay counselor, having more inclusive mental health attitudes, and retaining mental health knowledge as applicable to use during instructional time or incorporation into the knowledge transfer process, their primary duty. By contrast, quantitatively, teachers' attitudes appeared to become more inclusive on the study-specific survey pre versus post-training, but reverted to pre-training levels post-intervention. Teachers' mental health knowledge on the summative assessment did not change pre-training versus post-training versus post-intervention. CONCLUSIONS: Training, supervision, and serving as lay counselors led to teachers' willingness to serve as lay counselors. Teachers served as lay counselors by utilizing therapeutic techniques during class time and incorporating them into their typical instruction, not through delivering traditional office-like care. Teacher practices may be pointing to the potential emergence of an "education as mental health therapy" system of care. Their changes in attitudes and knowledge reflected their emerging practices. Quantitative measures of knowledge and attitude changes did not capture these nuanced changes. Trial Registration The parent feasibility trial was registered on January 01, 2018 with Clinical Trials Registry - India (CTRI), reg. no. CTRI/2018/01/011471, ref. no. REF/2017/11/015895. http://ctri.nic.in/Clinicaltrials/pdf_generate.php?trialid=21129&EncHid=&modid=&compid=%27,%2721129det%27. .