In parent-education practice nurses use Learning Principles (LPs) when helping parents to develop the knowledge and skills required to care for their children. LPs are basic precepts of learning, comprising people's beliefs, behaviors and reasoning processes. LPs underpin parents' active engagement, confidence building and decision-making, as information provided becomes usable knowledge. However, the ways nurses apply LPs in parent-education practice are poorly explained in healthcare. Likewise, descriptions of parents' learning experiences, associated with the use of LPs in nurse/parent-education interactions, are lacking. This study aimed to explore and describe nurses' perceptions and use of LPs, and parents' learning experiences in one healthcare organization. Participants and Methods: Using an action research design, 25 nurses and 18 parent participants were purposively recruited across metropolitan Adelaide, Australia. Data were collected through observations and semi-structured interviews and thematically analyzed simultaneously June-December 2017. Results: The LPs nurses used, and those important to parents' learning experiences created three overarching themes: 1) collaborative relationships, 2) deepening learning insights, 3) the learning environment. Despite their apparent use, nurses struggled to explicitly describe how they perceived LPs, believing their knowledge and use was sub-conscious − tacit. However, tacit knowledge hinders communication and explanation of LPs used within parent-education to other nurses. The member-checking of interview data helped to stimulate the nurses' metacognition (thinking about their thinking), unlocking their LPs awareness. Conclusion: Nurses used LPs in practice but their knowledge was tacit. Through metacognition, nurses started to recognize the ways LPs influenced their practice and parents' learning capabilities. Increasing healthcare constraints, including time allowed for parenteducation, require nurses to optimize their use of LPs. Future research should identify ways nurses can communicate their use of LPs, potentially enhancing parents' active learning experiences and concordance with health recommendations.