This paper examines the perceptions of Greek secondary education teachers on effectiveness in teaching. Through a structured questionnaire, 340 teachers reported their views on the tactics which are considered to contribute to effective teaching and on the behaviour and personal traits attributed to effective teachers. Descriptive and factor analysis showed that teacher flexibility in knowledge dissemination and sociability in communication, the display of friendliness, open-mindedness, tactfulness, supportiveness, respect and humour, are considered, among others, to be outstanding attributes of an effective teacher. However, the inflexibility of Greek curricula and their obsession with academic performance objectives discourage teachers from implementing effective instructional strategies, from establishing real human relationships with their students and from displaying behaviour and developing personal traits attributed to effective teachers. (Contains 4 tables.)