The studies on humor in the classroom have increased by far in recent years. This shows the importance of humor in teaching but also contributes in the clarification of teachers’ perceptions and practices about humor and the terms and conditions for humor’s presence in the classroom. In this frame we investigated the perceptions of 771 teachers of elementary school in Greece concerning humor in their teaching. More concretely we examined the perceptions of teachers concerning the advantages of humor but also the likely dangers that may come from it, the frequency and the forms of humor that they use in their teaching and finally their more general appreciation for the importance of humor in their school life and in their life in general. The analyses show that teachers are very positive towards humor, they rate it very highly relative to other elements of teaching, recognize the same positive effects that research has highlighted, but they also recognize some negative aspects (aggressive/hostile humor: irony, sarcasm).