Health utilization and need assessment data suggest there is considerable variation in access to outpatient specialist care. However, it is unclear if the types of barriers experienced are specific to chronic disease groups or experienced universally. This systematic review provides a detailed summary of common and unique barriers experienced by chronic disease groups when accessing and receiving care, and a synthesized list of possible health service initiatives to improve equitable delivery of optimal care in high-income countries. Quantitative articles describing barriers to specialist outpatient services were retrieved from CINAHL, MEDLINE, Embase, and PyscINFO. To be eligible for review, studies: were published from 2002 to May 2014; included samples with cancer, diabetes mellitus, osteoporosis, arthritis, ischaemic heart disease, stroke, asthma, chronic pulmonary disorder (COPD) or depression; and, were conducted in high-income countries. Using a previously validated model of access (Penchansky and Thomas' model of fit), barriers were grouped according to five overarching domains and defined in more detail using 33 medical subject headings. Results from reviewed articles, including the scope and frequency of reported barriers, are conceptualized using thematic analysis and framed as possible health service initiatives. A total of 3181 unique records were screened for eligibility, of which 74 studies were included in final analysis. The largest proportion of studies reported acceptability barriers (75.7 %), of which demographic disparities (44.6 %) were reported across all diseases. Other frequently reported barriers included inadequate need assessment (25.7 %), information provision (32.4 %), or health communication (20 %). Unique barriers were identified for oncology, mental health, and COPD samples. Based on the scope, frequency and measurement of reported barriers, eight key themes with associated implications for health services are presented. Examples include: common accommodation and accessibility barriers caused on service organization or physical structure, such as parking and appointment scheduling; common barriers created by poor coordination of care within the healthcare team; and unique barriers resulting from inadequate need assessment and referral practices. Consideration of barriers, across and within chronic diseases, suggests a number of specific initiatives are likely to improve the delivery of patient-centered care and increase equity in access to high-quality health services.