The use of khat (Catha edulis) is a major public health and social problem that is believed to be growing globally. The khat chewing habit is prevalent in all areas of the Jazan region, Kingdom of Saudi Arabia (KSA). However, few studies have been conducted at the community level to investigate the khat chewing habits in this area. This study was conducted with the aim of assessing the prevalence and predictors of khat chewing among the Jazan community population. A cross-sectional study was conducted with a sample (n = 4,500) of the Jizani population who attended primary heath care centers in Jazan region. The participants were selected using a two-stage cluster random sampling. A structured questionnaire was used for data collection. The overall lifetime prevalence of khat chewing was 33.2% (95% CI 31.8-34.7) and was significantly higher for males 42.2% (95% CI 40.4-43.9) than for females 11.3% (95% CI 9.6-13.1) (P < 0.001). Current khat chewers accounted for 28.7% (95% CI 27.4-30.1) of the population sampled; 36.9% (95% CI 35.2-38.6) of whom were males, which is a significantly higher percentage than the 8.7% (95% CI 7.3-10.4) of current khat chewers who were females (P < 0.001). The multivariate logistic regression analysis suggests that the most important independent predictors of khat chewing were having a friend who chewed khat (OR = 20.1, P < 0.001), participant's smoking status (OR) = 3.9, P < 0.001), friend's smoking status (OR = 2.2, P < 0.001), gender (OR = 2.2, P < 0.001) and educational level (OR = 1.5, P < 0.05). A large proportion of the Jizani populations chew khat. Government and non-governmental organizations NGOs should design and strengthen community prevention programs to curb the high prevalence of khat use.