This study investigates K-12 teachers' ICT competence levels, the differences in teachers' ICT competences based on their demographic characteristics, and factors that have an impact on their ICT competences. The data were collected from 1,429 K-12 teachers by means of a questionnaire. The findings of the study indicate that the majority of the participants do not perceive themselves as competent in basic and advanced ICT. Gender, prior preservice education ICT courses, and computer ownership are significantly related to the perceived ICT competences of K-12 teachers. Personal interest, possession of a home computer, and family and friends were rated as the most influential factors in acquiring ICT competences.