A study investigated the differences in perception of job insecurity among secondary school teachers in Israel. Of the entire sample, 205 teachers (62 percent) were affiliated with public-sector unions. The rest of the samples--121 teachers (38 percent)--were affiliated with the private sector and were non-unionized. Using a multidimensional approach, unique job insecurity profiles of teachers in the public and private sectors were drawn, and the resulting effects on work attitudes were analyzed. In these two sectors, job security is commonly viewed differently. In the public sector, jobs are normally seen as secure, while the opposite is true for the private sector. Job insecurity was found to adversely affect various work attitudes in both sectors, especially the public ones. The two sectors are clarified, a conceptualization of job insecurity is presented, and, finally, a description of the research population (secondary school teachers in Israel) is given. The report concludes that job security is not merely a question of keeping one's job, but encompasses various features and aspects of the whole job. The results of this study might be relevant to organizations undergoing change, where change instills job insecurity, on one hand, but paradoxically also demands the best work force possible, on the other. Tables present outcomes of job security related surveys and tests. (JMD/Author)