There is an increased focus on schools and school systems to develop teaching teams to improve school teaching and learning practices. As such, effectual school leadership has become synonymous with creating the conditions for teachers to work collaboratively to improve school teaching and learning. Middle leaders, teachers who are formally appointed to a leadership role, operate between senior leaders and teachers, are often responsible for leading teacher teams and facilitating the communicative space so that collaboration leads to positive outcomes for teacher practice and student learning. However, there is a lack of conceptual understanding of the micro-processes middle leaders enact when facilitating teacher teams and how facilitation impacts new or different teaching and collaborative practices. Drawing on the theory of practice architecture, we interrogate data from interviews, observations, and artefacts in three case study schools in Australia, to understand facilitation through the modes of action (doings), forms of understandings (sayings), and ways in which participants relate to one another and the world (relatings). Analysis of data revealed middle leader facilitation is consequential to how teacher team operate and that six ecologies of facilitation practices are typically enacted by middle leaders: procedural management, regulating interactions, expert guidance, purposeful dialogue, decision-making, and social-emotional support.