Experiencing broad play and interaction opportunities is known to support children's learning and development and engagement with museum collections has the potential to stimulate enriching learning opportunities for even the youngest enquiring minds. Here, we describe the development of Toddler Time; a museum-based early years program developed by the Ashmolean Museum, Oxford, UK, in partnership with researchers (including a speech and language therapist and a developmental psychologist). The program lead was trained to promote responsive interaction strategies within its gallery-themed sessions. Such strategies included "waiting to see what the child is interested in first" and responding to child initiations through "repeating back and expanding." Opportunities for self-reflection and review of adherence supported program refinements and enabled the lead's implementation to shift from using more traditional didactic practice during earlier sessions to providing increased opportunities for responsive interactions later in the program's delivery. Accommodating different ages and stages of development also progressed over time.