The study has been conducted on a sample of 600 Govt. Senior Secondary School Teachers of Haryana State to examine the effect of sense of humour on classroom performance of senior secondary school teachers. In this study classroom performance was treated as dependent variable whereas sense of humour was treated as independent variable. The random sampling technique was used to select the sample. The data were analyzed statistically by using mean, S.D. & t-test. The findings of the study revealed that significant difference exists between the classroom performance of senior secondary school teachers with high and low sense of humour. Significant difference was also found between the classroom performance of male, female, rural and urban senior secondary school teachers with high and low sense of humour.