This descriptive multi-case study systematically explored the team teaching relationship between a secondary teacher and a university faculty member. Multiple interviews, classroom observations, and analysis of available data provided insights into the interactions of these particular collegial-teams, drawn together for the purpose of providing rigorous STEM curriculum to high-ability students during a three-week residential program. Data revealed that successful collaboration can be described by the emergent themes of reciprocity, respect, flexibility, and time. It appears that an active interchange, or reciprocity, and mutual respect between partners during curriculum/lesson/unit planning, instructional delivery, and assessment facilitate effective collaborative instruction. Findings further revealed that instructors expressed an overall positive experience with collegial-teaming; one that has been valuable to them as professionals. The university instructors reported acquiring and improving upon their own pedagogical skills, while the high-school instructors reported gains in terms of obtaining in-depth content knowledge. The partnership also assisted in bridging insights between the secondary and college arenas in terms of content and academic expectations at both levels. The overall experience provided professional growth and development that would not have occurred without the unique pairing of a high-school instructor and a university faculty member.