Background: Trainee doctors undergo a complex process of emotional labour at the workplace. The presence of any negative emotion affects not only their professional and caring competency but also their mental health. The purpose of this study is to identify the use of different emotion regulation (ER) strategies in Sad, Disgust, Fear, Anger, and Shock situations, and to determine the frequency and the predominant pattern of emotional response in the emotion triggering situations. Methods: This cross-sectional study was done in two public and one private-sector medical college in Lahore, Pakistan, in 2019. Gross Theory of emotion and situational model of emotion regulation was used to develop a questionnaire and to interpret the findings. Based on Gross Theory, emotion regulation strategies were situation selection (SS), situation modification (SM), cognitive change (CC), attention deployment (AD), and response modulation (RM). The results were analysed using chi-square and repeated-measures ANOVA on SPSS 25.Results: Out of the 377 trainees, 308 participated in this study. Most of them were from the Obstetrics & Gynaecology (43.2%) department and in the Year-1 of training (37.7%). The most frequent emotion triggering situation was prolonged working hours (95%). The major emotional response was quietness (50%) and this reaction was observed in situations of the rude behaviour of patients and their attendants toward staff (60%). The trainees used greater ER strategies in sad situations (Mean 3.49 ± 1.79; F=1823, p <0.01). Trainees managed sad emotions by keeping themselves involved in other activities (49%) and with an outward response (50%). In anger; they blamed others (40.3%) and ruminated (32.8%). In fear; suppression of emotions (28.6%) and focus on the task (23.1%) were the most common ER strategies. When disgusted, avoidance (29.2%); and suppression of emotions (28.9%) were used. In shock, acceptance (12.7%) and suppression of emotion (8.4%) were preferred ER strategies. Conclusion: Trainees struggle to manage emotions and use maladaptive strategies that are avoiding situations, focusing on other activities, blaming others, rumination, thought suppression, and outward behaviours. Developing emotional skill programs to manage negative emotions can improve mental health, job satisfaction, and patient care.