Teacher motivation is by and large the major determinant of students' success during the schooling process. This is primarily because a motivated teacher is likely to be more engaged and enthusiastic in the workplace. Kenya's education sector has in the recent past experienced industrial disharmony which has been occasioned by teachers' demand for higher remuneration. This demand, however, could be a pointer to the existence of other unmet needs among teachers in the country. This is what informed the study whose overall objective was to determine whether besides compensation other factors, specifically work environment, opportunities for career progression, performance appraisal, recognition and training opportunities could also be impacting teachers' motivation in public secondary schools in the country. Additionally, the study sought to establish the relative influence of the six factors (predictor variables) on teachers' motivation (criteria variable). Data were collected through a self-delivered questionnaire from 255 teachers who were randomly selected from 752 teachers in public secondary schools in Kwale County. Data were analyzed by way of arithmetic mean and multiple regression analysis at 0.05 alpha level. The findings demonstrated that the factor that had the highest teachers' motivation impact was opportunities for career progression (mean=3.720; [beta]=0.238), followed by compensation (mean=3.477; [beta]=0.175), recognition (mean =2.489; [beta]=0.0168), performance appraisal (mean =2.410; [beta]=0.120), training opportunities (mean=2.388; [beta]=0.075) and lastly work environment (mean =2.053; [beta]=0.041).The six predictor variables accounted for 81% of total variation in teachers' motivation. These findings have important lessons and implications for teachers' motivation in the country. Specifically, teacher managers at the school and national level should rethink their approach to teachers' motivation. In particular, they need to not only focus on teacher remuneration but also the unmet needs in areas relating to work environment, performance appraisal, training opportunities and recognition.