MTSS stands for Multi-Tiered Systems of Support. MTSS is a process for providing support for students who need additional support using a tiered approach. It is important to note that students do not need to pass through all tiers to be evaluated for an IEP, though movement through tiers can provide data that might help inform an IEP. Find more here: https://www.understood.org/en/learning-thinking-differences/treatments-approaches/educational-strategies/mtss-what-you-need-to-know