Bass Transformational Leadership Theory is a leadership approach that focuses on how leaders can create valuable and positive change in their followers. Bernard Bass built upon the work of James MacGregor Burns to develop an expanded and more detailed version of transformational leadership theory. According to Bass, transformational leaders demonstrate four factors: individual consideration, intellectual stimulation, inspirational motivation (charismatic leadership), and idealized influence.

Bass defined transformational leadership in terms of how the leader affects followers, who are intended to trust, admire, and respect the transformational leader. He identified three ways in which leaders transform followers: idealized influence, inspirational motivation, and intellectual stimulation. Idealized influence refers to the charisma of a leader who appears to be special, acts as a role model for followers, and has strong ethical and moral values. Inspirational motivation describes how transformational leaders encourage their followers to see a vision and exhort them to do things. Intellectual stimulation describes how transformational leaders encourage their followers to question not only their beliefs and values but also those of the leader. Through this rigorous and open examination, Bass believes that opportunities for personal growth, innovation, and creativity are discovered.

Bass Transformational Leadership Theory assumes that the leader has a decent set of ethics, but if the theory is applied in a situation where a leader does not, the results could be disastrous. The theory is supported by nearly 30 years of research correlating transformational leadership to positive performance outcomes including individual, group, and organizational level variables. However, research on the theory is primarily based on the multifactor leadership questionnaire, which has produced inconsistent results. Transformational leadership also has the potential to be used negatively by leaders "faking it".