Layoffs and alternative staffing seem to be a phenomenon in many workplaces, many employees seem uncertain of their continuing in their job as a result of threats that they face on the job which could lead to job loss, and these call for concern. This paper therefore examines some of the factors responsible for job insecurity and employee turnover and the attendant effects of job insecurity on organisation. The study investigates the relationship between job insecurity and organisation performance, as well as relationship between job insecurity and employee turnover. Self-developed structured questionnaire titled ‘Job Insecurity, Organisation Performance and Employee Turnover’ (JIOPET) was used as the instrument to collect data from one hundred and twenty randomly selected respondents from organised private sector (financial institutions) in Akure and public sector (state secretariat) in Ibadan, Nigeria. The data were analysed and the two hypotheses drawn up for the study were tested using Pearson Product- Moment Correlation. The findings establish that job insecurity negatively affect organisation performance and induce employee turnover. It is recommended that organisation policy makers should diligently address the factors that contribute to job insecurity, have training policy and train employees as work procedures are becoming more dynamic with new technologies.