The purpose of this study has threefolds: (1) to explore teacher developmental stages, (2) to determine the need of job competence for elementary school teachers based upon teachers' development stages and finally to set the priorities of the identified needs. 311 elementary school teachers in Seoul Metropolitan School District were participated in this study (valid response rate: 72.7%). The major findings of this study are as followed: (1) six job competence clusters and 37 sub-job competences for teachers were identified. (2) more than 70% of teachers were in the developmental stage of either growth or maturity. (3) three stages of teacher development were identified as the self-adequacy focusing on survival, the mediation among growth, stability, and frustration, and finally maturity/promotion. (4) teachers at the stage of mediation tended to have higher needs of job competences than those at the stage of maturity/promotion. (5) regardless of developmental stages, the understanding of teaching and learning methods, the practice of instruction strategy according to situation, and the theory and practice of school counseling were appeared as common job competences. Also there are different needs of job competences based on developmental stages. Finally, this study proposed some theoretical and practical implementations.