This study examined the factors that affect teacher classroom Internet use and teacher self-efficacy with using the Internet. With regards to classroom Internet use, the factors examined were grade taught, years of teaching experience, type of school technical support, Internet-related professional development training, number of Internet-accessible computers in the classroom, student socioeconomic status, and teacher Internet self-efficacy. For teacher Internet self-efficacy, the factors examined were years of teaching experience, type of school technical support, and Internet-related professional development training. This study surveyed 419 public school teachers, across grades K-12, using stepwise multiple regression to analyze the factors and their relationships with classroom Internet use and teacher Internet self-efficacy.;The results from the 419 survey respondents indicate that grade taught, number of Internet-accessible classroom computers, school socioeconomic status, and teacher Internet self-efficacy were all significant predictors of classroom Internet use. In-service training and multiple-day workshops were also found to be significant predictors of classroom Internet use, but the variable college credit courses was not. Further, the factors of years of teaching experience and type of technical support were not significant predictors. The data for teacher Internet self-efficacy indicated that years of teaching experience was a negative predictor of self-efficacy, while all three types of professional development were a positive predictor. Technical support was not a predictor of teacher Internet self-efficacy