The evaluation of English Language Teaching (ELT) materials plays a critical role in ensuring their effectiveness in developing students’ educational attainment levels in line with national standards. Although numerous studies have examined ELT materials in Saudi Arabia, the majority have focused on general aspects such as content suitability, cultural appropriateness, and overall pedagogical design. Consequently, a significant research gap remains concerning the effectiveness of these materials in fostering students’ educational attainment levels in receptive skills. This study addresses this gap by evaluating the effectiveness of the Mega-Goal textbook series on Saudi EFL students’ educational attainment levels in receptive skills. The evaluation focused on three key aspects. First, it assessed the overall effectiveness of the Mega-Goal series in developing Level 3 graduates’ receptive skills attainment in alignment with the National Qualifications Framework for Saudi Arabia (NQF-KSA). Second, it examined the extent to which the Mega-Goal 3 textbook reinforces Passive Learning Approach (PLA) or Active Learning Approach (ALA) in the content and format and presentation of its listening and reading sections. Third, it investigated the correlation between ALA reinforcement in the textbook content and graduates’ actual attainment levels. Adopting a convergent parallel mixed-methods design, the study collected quantitative data from 48 Level 3 graduates through the EF Standard English Test (EF SET) and a survey, and qualitative data through a deductive content-analysis codebook and semi-structured interviews with five EFL teachers. Data were analysed using descriptive statistics, one-sample t-test, Pearson correlation with simple linear regression, and deductive thematic analysis. The findings indicate that the Mega-Goal textbook series is ineffective in developing students’ educational attainment levels in receptive skills, with graduates achieving A2 level rather than the expected B1–B2 range. The Mega-Goal 3 textbook was found to predominantly reinforce PLA in both content and activities. A moderate positive correlation was observed between the interactivity principle and attainment levels in receptive skills. The study concludes with important pedagogical implications and recommendations for enhancing ELT materials in Saudi Arabia to better support competency development and alignment with national standards.