The purpose of the study was to investigate teachers’ emotional social intelligence and its relationship with classroom learning environment. The main objectives of the study were to; investigate emotional social intelligence of university teachers, find classroom learning environment at university level, measure the relationship of teachers’ emotional social intelligence with the classroom learning environment, investigate gender-wise, sector-wise and discipline-wise differences in emotional social intelligence (ESI) of teachers at university level. Research questions were formulated. Sequential explanatory mixed method design were adopted. All teachers and students of the twenty nine public and private sector universities of khyber Pakhtonkhwa- Pakistan constituted the targeted population of the study. While the actual population of the study was nine (9) universities teachers and students. Propotional stratified random sampling techniques and Purposive sampling techniques were adopted for selection of representative sample group from population. Questionnaires and interviews were used as research instruments to collect data from the concerned participants. Self-developed questionnaire was used to measure teachers’ emotional social intelligence at university level. Interviews were conducted to measure student’s perception about teachers’ emotional social intelligence. WIHIC (What is hapning in this classroom) questionnaire was adopted to investigate classroom learning environment. The collected data were analyzed through Statistical techniques like mean, standard deviation, independent sample t-test, Cohen’s D calculater, ANOVA, Pearson correlation and thematic analysis. In conclusion a moderate significant correlation were noted between emotional social intelligence of university teachers and classroom learning environment. Male emotional social intelligence was higher than female, while no significant differences were noted in public and private sector university teachers’ emotional social intelligence. For future researchers, it was recommended to design a study to investigate those factors that directly contribute and affect into the development of emotional social intelligence of teachers and students. It is recommended that future researchers may conduct research studies with different research designs and approaches at higher secondary, secondary and primary level. Further it was recommended to investiage CLE in relation to the emerging qulity concerns on the academic acheivement of students at university level.