By adapting a self-administered assessment of coparenting, we sought to provide a new tool, the Cocaring Relationship Questionnaire, to measure parent-teacher, or cocaring relationships, and provide additional construct validity for the multidimensional concept of cocaring. Next, recognizing the importance of parental involvement for young children's development, we examined the associations between dimensions of cocaring and aspects of parental involvement. We investigated the parent-teacher relationships of 90 families utilizing full-time, center-based childcare for their 12-36 month old children. Parents and teachers completed a set of questionnaires. Research findings: exploratory factor analysis revealed a four factor structure for the cocaring relationship: Support, Undermining, Endorsement, and Agreement. After controlling for a number of child- and parent-level covariates, parents' perceptions of different dimensions within the cocaring relationship were associated with different aspects of their self-reported and teacher-reported involvement. Most notably, parents' perception of cocaring support was positively associated with three different forms of parental involvement. Practice or Policy: the Cocaring Relationship Questionnaire offers researchers and practitioners a means to assess multiple dimensions within parent-teacher relationships. Understanding that parent-teacher relationships are multifaceted can help practitioners consider their interactions with families in new ways, which may influence, or be influenced by, parental involvement.