Today, higher education, as the main driver of science and technology, plays an important role in advancing the goals of countries for comprehensive and sustainable growth and development. Challenges of higher education include "quality assurance" and "university ranking" in higher education, which are specified in the upstream policy documents, but their differences are not mentioned. Therefore, the study of the dimensions of each of these two approaches to assess the quality of higher education is necessary to provide the requirements for their implementation. Therefore, the purpose of this study is to answer the question of what are the differences between these two evaluation approaches in the available sources. Thus, the statistical population of the current study considered all the texts related to the dimensions and characteristics of quality assurance and academic ranking in higher education and sampling was done purposefully to answer the research question. Then, by adopting a qualitative approach and using the documentary research method, the sources were examined until the theoretical saturation was reached. Findings indicated that in "quality assurance", the main function is quality improvement and increasing accountability, the method of evaluation is criterion-based and formative, and its audience is often the academic community. But in "university ranking" the main function is governing the higher education sector, the method of evaluation is comparative and summative, and its audience is the general public and the academic community. Finally, due to the differences between the two approaches, suggestions were made for their prioritization and implementation.