The aim of the research discussed in this paper was to determine the relationship between the staffing practices – such as recruitment, promotion and transfers- of the Teachers’ Service Commission and pupils’ academic performance in public primary schools in Merti sub-county, Isiolo County, Kenya. The research had one objective and one research question. Using descriptive survey research design the target population consisted of 29 primary schools with 29 Headteachers and 166 teachers all employed by the Teachers’ Service Commission. Purposive and simple random samplings were used to select the respective head-teachers and teachers yielding a total sample size of 29 head-teachers and 145 teachers as actual respondents. Data were collected using questionnaires and analyzed using appropriate descriptive statistics including frequencies and percentages which were presented in form of tables, bar graphs and pie charts. The findings revealed that improper staffing practices influenced pupils’ academic performance to a moderate extent. For instance, delay in promoting teachers coupled with ambiguity in teacher transfer procedures negatively affected their morale in teaching. The research recommends that the Teachers’ Service Commission needs to develop fair criteria for deployment, transfer and promotion of teachers