This study determined the relationship between In-Service training and Geography teachers’ job performance in public senior secondary schools in North-east zone, Nigeria. Two research questions were raised and two hypotheses formulated to guide the study. The population of the study comprised all Geography teachers and principals in public senior secondary schools in North-east zone, Nigeria. The sample was 400 geography teachers and 107 principals selected using Yount technique of sample size determination. A correlational research design was adopted. The instrument used for data collection was questionnaire titled “In-Service Training and Geography Teachers Job Performance Questionnaire” (ISTGTJPQ). In order to provide for face and content validity, the instrument for data collection (ISTGTJPQ) was subjected to thorough scrutiny and vetting by four experts, one in Geography Education and two in Biology Education from the department of Environmental and Life Sciences Education and one in Mathematics Education department of Physical Sciences Education, Modibbo Adama University, Yola. The reliability coefficient of the instrument was established using Cronbach Alpha statistic and the coefficient was 0.78. A Descriptive statistic of mean and standard deviation was used to answer the research questions while Pearson product moment correlation method was used to test the hypotheses at 0.05 alpha level. The study revealed that: There is a high significant relationship between In-Service Training and Geography Job Performance in Public Senior Secondary Schools in North-East zone, Nigeria as shown by high and significant relationship between Teachers pedagogical content knowledge and geography teachers’ job performance, represented by [r (r) = 0.81; p<0.05)]. Furthermore, the revealed that there is a high significant relationship between In-Service record keeping and geography teachers’ job performance in public senior secondary schools in North-east zone, Nigeria as indicated by [r (r) = 0.84; p<0.05)]. It was therefore concluded that In-Service training had a high and significant relationship on geography teachers’ job performance in public senior secondary schools in north-east zone, Nigeria. It was recommended among others that Principals should ensure that geography teachers put into practice their pedagogical knowledge in the teaching-learning process in order to achieve their content knowledge, this is possible if the principals carry out regular supervision on teachers’ classroom activities in public senior secondary schools in north-east zone, Nigeria.