The current study aimed to identify the degree of the impact of academic preparation on the acquisition of leadership behaviour among principals of secondary schools in Jordan, from the teachers' points of view. The study followed the descriptive survey method. The researcher used the questionnaire as an instrument that comprised (30) items, distributed into five disciplines: The "rules' formation", "common vision", "challenge", "empowerment", and "encouragement" respectively. The study instrument was applied to a randomly chosen sample of (175) male and female principals from secondary schools in the Ajloun Governorate. The researcher found out the following results: The degree of the impact of academic preparation of giving leadership behaviour to secondary school principals came with an average degree level for all dimensions. The dimensions came in a descending order as follows: The "common vision", "rules' formation", "empowerment", "encouragement", and" challenge". There were no statistically significant differences at the level of significance (0.05≥α) among the sample individuals' responses to the degree of the impact of the academic preparation of the Jordanian secondary-school principals' acquisition of leadership behaviour in terms of the (gender, experience, and scientific qualification) variables. The researcher recommended the intensification of training courses in the five fields (the "common vision", "rules' formation", "empowerment", "encouragement", and "challenge") to develop leadership behaviour among high school principals in Ajloun Governorate. Besides, reliable external or internal parties should conduct an annual evaluation of the training courses and activities provided by the Ministry of Education, receiving feedback from educational supervisors in the field regarding the success of these courses and their impact on the behaviour of secondary school principals.