The study examines grammatical errors made by online English instructors, particularly those with large audiences. It highlights concerns over unqualified instructors spreading incorrect language and using poor teaching methods, which can hinder learner proficiency. The research aims to identify the most common grammatical errors and explore gender differences in error frequency. Using a qualitative approach and Corder’s (1973) Error Analysis Model, supplemented by Norrish’s (1983) and Dulay and Burt’s (1974) models, the study analysed five transcribed samples. Results indicate that instructors frequently make grammar mistakes, which may negatively influence learners’ language habits. The findings also show a gender imbalance, with male instructors being more prominent. The study concludes by emphasizing the importance of continuous linguistic training for online instructors.