Teacher wellbeing has taken on increased importance in understanding contextual variables related to student academic, social-emotional, and behavioral growth. Despite its importance, little is known about how wellbeing and stress change throughout the school year. Single item measures may be a viable alternative to lengthy rating scales, particularly when measuring constructs across multiple time-points; however, further information is needed to understand the psychometric defensibility of these tools. The current study aims to address current limitations in the literature through a multifaceted examination of teacher stress, efficacy, and school connectedness. Specifically, the study explores the concurrent validity of three single-item measures by examining correlations between single-item scales and the Teacher Subjective Wellbeing Questionnaire (TSWQ). Second, the study investigates changes in teacher wellbeing and stress across a school year via a weekly report of stress, efficacy, and school connectedness. Participants included 158 middle school teachers from a large, diverse district in the Northeast United States. Results indicated moderate to strong correlations between teaching efficacy and school connectedness single item measures with long-form rating scales of teacher wellbeing. In addition, teacher stress increased by nearly 20% from October to June, while school connectedness and teaching efficacy declined by a similar amount. Implications for assessment and intervention to support teacher wellness are discussed.