This scholarly essay explores the challenges that teachers face in implementing the Nueva Escuela Mexicana (NEM) [new Mexican school] educational model, which prioritizes project-based and interdisciplinary learning over subject-based instruction. The NEM's flexible approach requires teachers to independently structure lessons, ensuring continuity without a predefined thematic sequence. Collaboration is essential, yet many educators struggle with interdisciplinary coordination, especially in secondary education. Limited planning time and curricular flexibility further complicate implementation. Teachers in marginalized areas also face resource constraints, which hinder project-based learning. Additionally, the NEM's textbooks, which are designed for integrative learning, lack clear organization and guidelines, making them difficult to use. These challenges highlight the need for greater support and structured collaboration to successfully adapt to the NEM framework.