Children with a severe communication disability who are unable to use speech for everyday communication are said to have complex communication needs. This disability may be due to physical, psychological, and/or cognitive impairments; and commonly results in a variety of activity limitations and participation restrictions. Augmentative and alternative communication (AAC) systems are often introduced to these children by speech-language pathologists (SLPs). When embraced by the child's parents and modelled in a variety of environments, AAC can result in significant benefits for the child's communication and quality of life. Many parents however reject the idea of AAC from the outset or attempt and later abandon use of the system, thus impacting their child's communication development and success. Despite the implications of AAC rejection and abandonment, this phenomenon has seldom been explored in the literature. Therefore, the series of studies described in this thesis sought to understand why parents of children with complex communication needs may reject or abandon the AAC system introduced to their child. This objective was achieved via a systematic review, three qualitative descriptive studies, and a correlational quantitative investigation. The systematic review aimed to synthesise the barriers and facilitators to the provision and use of low-tech and unaided AAC systems. Relevant literature was identified via a systematic search strategy and qualitative framework analysis was then completed with reference to the International Classification of Functioning, Disability, and Health (ICF). Most barriers and facilitators were coded as contextual factors (i.e., environmental and personal factors) within the ICF. Of most prominence were environmental factors including the attitudes and supports of professionals, family members, and society at large. For example, both parents and SLPs held misconceptions about AAC and lacked time to support the implementation of an AAC system. Additional environmental factors related to the AAC I acknowledge that an electronic copy of my thesis must be lodged with the University Library and, subject to the policy and procedures of The University of Queensland, the thesis be made available for research and study in accordance with the Copyright Act 1968 unless a period of embargo has been approved by the Dean of the Graduate School.