The interest to all actors and observers within educational arena denotes a long-term trend of expansion of educational professionalism accompanied by a continuous debate about its desirability, and a perennial instability or dynamic of the structures within education systems. Over the years, however, the emphasis placed on shape of professionalism in education systems has varied substantially to reflect the complexity contained therein from a purely managerial and leadership perspective. Moreover, we observe considerable changes of "views and controversies'' concerning the most desirable quality and structure of teacher interaction and professionalism in educational institutions. This chapter explores the state of teacher interaction and collaboration in educational institutions as well as dissecting implications of same for management and leadership in schools. The study is deemed an eye opener to managers, leaders in schools to 'mind the gap' that is teacher insularity if they are to effectively achieve the very best out of them.