Student affairs are considered in assessment guidelines as criteria of quality at Higher Education Institutions. In Spain, the National Plan for Quality Assessment include three fields of assessment: teaching, research and services. In the analysis of these fields of assessment, we find explicit references to the functions of support to students, which are considered as a quality criterion in the assessment of teaching. However, service assessment doesn't mention which services must be assessed, what results in a lack of information as to the required minimum services every university should offer. Approach and methodologyThe objectives of this study are: 1. To know the functions that comprise the student support system at Higher Education institutions and compare them with the Assessment Guidelines used in the National Plan for Quality Assessment.2. To determine the functions related to student support at Spanish universities which are considered indispensable and which, therefore, could be used as quality criteria for assessing the quality of universities.The methodology followed in this study was twofold: (a) literature review and content analysis for objective 1, and (b) a 50-items questionnaire aimed at persons in charge of student services at universities.Results and conclusionsLiterature review and content analysis have shown that there is a wide range of functions that constitute the student support system. When comparing these functions with the ones in the Assessment Guidelines some of them are not considered in the guidelines, for instance: support to disabled students, careers guidance aimed at students and employers, mechanisms for identifying student needs and making complaints and suggestions, financial and legal advice, etc.The main results of the questionnaire allow us to establish criteria related to student support in institutional assessment and/or accreditation. In order to establish these criteria, every item has been graded according to a Likert scale from 1 to 4 which has been summed up in two: 1 and 2 being considered as less necessary, and 3 and 4 as very necessary. With this measure, we have calculated the percentage of positive answers (3 and 4) establishing five groups in order of importance.The main conclusions of this survey are:Not all functions related to the same area (academic, careers, welfare, etc.) are considered equally important. This result confirms the need for dealing with the student support system through functions, instead of the traditional approach based on services focused on just one aspect and with no relation with the Faculties.Group 1 items could be considered as requisites in any university and that's the reason why they could be considered as criteria of quality at Higher Education institutions as regards student support. Items included in group 1 are: Sports and cultural infrastructures and activities, access of disabled students, careers guidance aimed at students and employers, guidance in order to access to the labour market, mechanisms for making complaints and suggestions, information about the university for freshmen and in secondary schools, guidance on financial aid and grants, and enrolment procedures and guidance for foreign students.Although Assessment Guidelines omit some functions of groups 1 and 2 considered as most important by persons in charge of student services, they don't include any of the functions included in groups 3 and 4, considered less important, what indicates a certain agreement. These functions make reference to the management of accommodation for students, legal and financial advice, psychological counselling not related with academic matters, and religious affairs.The information contained in the established groups can be useful both for revising Higher Education assessment guidelines in Europe and for those responsible for the improvement of the quality of universities to become more student-oriented.