‘Literature highlights the importance of effective communication as well as the impact of a positive school climate. The objectives of this research are to investigate principals’ communication skills and their effect in shaping school climate. A sample of 321 teachers of secondary schools in Greece was selected using proportionate stratified rand om sampling technique. Communication skills were assessed by a section of Multifactor Leadership Questionnaire when School Climate evaluated by a new questionnaire structured for this study and tested for its reliability and its validity. Descriptive statistics and Pearson correlation were used to check the two hypotheses of the study. The results revealed that principals in Greek schools, in Secondary education, have “a lot of” communication skills and that skills have significant, moderate positive correlation (r=0,338) with school climate. Findings could be used in principal’s training programs to practice effective communication techniques.