Student behavior and classroom management are consistently identified as top reasons teachers leave the profession. A descriptive phenomenological study was conducted in a suburban school district in north Texas to identify how teachers perceive the deficits in their classroom management knowledge and to provide school leaders with data to guide plans for professional learning about effective classroom management strategies. Findings are based on both teachers' and principals' perceptions of supports that are needed or provided. Nine teachers (three elementary, three middle, and three high school) and six administrators (two elementary, two middle, and two high school) were interviewed using semi-structured interview protocols. Data were analyzed using seven a priori codes from which themes were developed. The findings showed that teachers generally do not feel well-prepared to address student behavior and classroom management. Emerged themes from both teacher and principal interviews identified deficits in professional learning received from their teacher preparation program, campus leaders, and district leaders. The top reasons why teachers struggled with student behavior and classroom management were: (a) application of learning, (b) deficits in support, (c) deficits in training, (d) physical and emotional toll, and (e) student deficits in social skill development. To help teachers feel better prepared to address student behavior and classroom management, they need: (a) to spend time with a first-and second-year teacher cohort, (b) be part of a campus with a growth mindset culture, (c) increased campus administrator support, (d) increased coaching support, (d) increased district administrator support, (e) revamped teacher preparation programs with relevant learning, and (f) differentiated, targeted professional learning.