Every company suffers to find accurate way to approach their goal and maximize their performance due to survive in tough competitive business environment in recent era. Accordingly, this study aimed to provide two ways from both employers and employees that stimulate above and beyond task performance. Transformational leadership and work engagement comprise facts related to employers for ascending task performance whereby work engagement is a manner which is mediator between transformational leadership and employees task performance. Moreover, this study asserted transformational leadership has effective influence on work engagement. In addition, this study aimed to check moderation effect of Adversity Quotient on the relationship between work engagement and task performance. The study uses questionnaire with 60 questions which handled to both on the internet and through hardcopy to Mongolian organizations. Accordingly, 337 valid responses are gathered. The findings of the research result are as follows: (1) both the transformational leadership and work engagement have a positive influence on the task performance; (2) transformational leadership has a positive effect on the work engagement; (3) the work engagement is a partially mediator on the relationship between transformational leadership and task performance.