This study investigated the relationship between the preschool teacher personality traits determined using Costa-McCrae's Five Factor Model of Personality and the individual attitude toward inclusive education, and also examined whether this attitude was affected by teaching experience and professional development. The Neuroticism-Extraversion-Openness Personality Inventory (NEO-PI) and the Indonesian Version of the Multidimensional Attitudes Toward Inclusive Education Scale (MATIES VI) were administered to 90 Indonesian preschool teachers. It was found that the Openness to Experience trait correlated significantly with the cognitive domain of the teacher attitudes, with all five traits significantly correlating with the affective attitude domain, and all traits except Neuroticism correlating significantly with the behavioral attitude domain. Teaching experience, however, was not found to have any significant effect on teacher attitude, and the participants' affective domain scores differed depending on whether or not they had had inclusive education professional development. The implications of these findings are discussed in relation to international studies and suggestions given for effective inclusive education interventions for Indonesian preschool teachers.