This research study is one of the first of its kind (impact/effectiveness) carried on in the “Global South” and it is part of the ROER4D framework as subproject 9. The Research on Open Educational Resources for Development (ROER4D) project, led by the University of Cape Town, aims to provide evidence-based research from a number of countries in South America, Sub-Saharan Africa and Southeast Asia. The study aimed to examine the effect of the use of two Open Educational Resources (Khan Academy spanish website and Open Textbook hosted on Wikibooks) with respect to the increase of mathematical outcomes of first and second year higher education Chilean students and also to uncover teachers and student’s perceptions about the use of OER in order to understand how these resources are used and valued. For these purposes, quantitative and qualitative methods were used to analyse student performance data and data produced from the semi-structured interviews, focus groups and survey. Findings indicate that students part of a contact mode of a Mathematics course that used Khan Academy online Mathematics tutorial obtained better examination grades than students who did not use any extra resources or who used the Open Textbook. Moreover, it was also found that teachers and students have very positive perceptions about the use of both the Khan Academy and Wikibooks materials.