This study investigated the impact of teaching practice on teachers in training’ in tertiary institutions in Adamawa State, Nigeria. The study was guided by five research questions and two research hypotheses. The study adopted a descriptive research design. The population of the study consisted of 5,193 teachers in training in tertiary institutions in Adamawa State; while the sample size was 400 using stratified sampling technique. A structured questionnaire titled “Impact of Teaching Practice on Teachers in Training Tertiary Institutions (ITPTTTI)” was used for data collection. Two experts from the Department of Educational Foundations, Faculty of Education, Adamawa State University, Mubi validated the instrument, while a test-retest reliability conducted revealed a co-efficient of 0.81. The data gathered were analyzed using mean, standard deviation, and t-test analysis. The study revealed that: the level of adequacy teachers in training before teaching practice was good; faculty supervision of teaching practice in tertiary institutions in Adamawa State was low compared to expectation; teachers in training experience during teaching practice was found to be influential in shaping student teachers’ attitude towards the profession; teachers in training’ experienced a lot of challenges during teaching practice exercise which hindered successful realization and achievement of teaching practice aims and objectives; Thus, the study concluded that teaching practice had a positive impact on teachers. In training. The study recommended that universities and colleges of education should organize seminars, micro-teaching, workshops, conferences and discussion before teachers in training’ are sent for teaching practice. Furthermore, finance should be provided for teachers in training’ so as to boost their upkeep and their attitudes towards