Social emotional competence is an essential developmental skill recognized as the most critical for school and later success. Rising rates in behavioral referrals and preschool expulsion have brought increased attention to the importance of helping children develop social-emotional skills in the early years. In early childhood education a central factor of social-emotional/behavioral intervention is the competence of teachers to address children's needs. In order for the social-emotional needs of children to be addressed in early childhood classrooms, adequate preservice teacher training and support are needed. The current studies focused on preservice teacher training and support regarding social emotional assessment and behavior intervention. Two studies were included in this research: (1) an early childhood preservice teacher survey and (2) Social Emotional Assessment Measure (SEAM) Preschool Teaching Guide development and behavior support plan pilot study. The first study focused on early childhood preservice teachers' current knowledge and practices regarding social-emotional development and behavior support. Participants included 228 preservice teachers from early childhood education (ECE) and early childhood special education (ECSE) teacher training programs in 15 different states. ANOVA results and answer percentages and means revealed trends in training, implementation, and preparedness by program type and degree level. The second study addressed how to support early childhood teachers in the creation of behavior support plans linked to assessment results. It took place in two phases: (1) development of a preschool teaching guide for the SEAM, and (2) a behavior support plan pilot study using the SEAM Preschool Teaching Guide. Participants included 25 preservice early childhood teachers from ECE and ECSE programs. Results from a two-way repeated-measures ANOVA indicated that the teaching guide intervention significantly improved the behavior support plan quality scores of preservice teachers. Results were further analyzed by program type and degree level. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]