Mathematics teachers are increasingly being called to integrate mathematical modeling into their course sequences and curriculum (NCTM 2018; NGA Center and CCSSO 2010). Mathematical modeling is a dynamic cycle calling teachers to engage in complex instructional work that advances students' mathematical knowledge and reasoning. The modeling cycle includes practices such as posing real-world problems; making assumptions; identifying constraints and variables; building mathematical solutions; and analyzing, assessing, and iterating solutions with respect to the original assumptions (COMAP and SIAM 2016). To effectively address these calls, the authors believe that teachers need collective opportunities to identify and design instructional supports that advance students' opportunities to use modeling practices. This article highlights the collective efforts of a teacher, leader, and teacher educator team to design an instructional routine that supports students in learning important modeling practices and mathematics.