Libraries increasingly seek to support the mental health and well-being of students. This study reports on the results of a survey examining the range of such support activities offered by UK academic libraries prior to and during the COVID-19 pandemic. Prior to the pandemic libraries' emphasis was on new library specific services such as a fiction collection, a type of initiative taken to proactively align with institutional policy. During the pandemic focus shifted somewhat to addressing the anxiety related to finding e-resources. Drawing on the survey data a holistic model of library support for student mental health and well-being is developed, capturing its eight different aspects: inherent library value, library services impact, well-being as a library service, detection, hosting, signposting, library as a good partner and library staff well-being. This represents a framework through which to examine how an academic library can support student mental health and well-being, and complements the "whole university" approach being increasingly adopted in the UK.