BackgroundPeople living with chronic conditions and disabilities experience harassment both offline and on the web. Cybervictimization is an umbrella term for negative web-based experiences. It has distressing consequences on physical health, mental well-being, and social relationships. These experiences have mostly been documented among children and adolescents. However, the scope of such experiences is not well documented among adults with long-term conditions, and the potential impact has not been examined from a public health perspective.ObjectiveThis study aimed to examine the scope of cybervictimization among adults living with long-term conditions in the United Kingdom and the perceived impact on self-management of chronic conditions.MethodsThis paper reports the findings of the quantitative phase of a mixed methods study in the United Kingdom. This cross-sectional study targeted adults aged ≥18 years with long-term conditions. Using a web-based link, the survey was shared on the web via 55 victim support groups, health support organizations, and social media accounts of nongovernmental organizations and activists such as journalists and disability campaigners. People with long-term conditions were asked about their health conditions, comorbidities, self-management, negative web-based experiences, their impact on them, and support sought to mitigate the experiences. The perceived impact of cybervictimization was measured using a set of questions on a Likert scale, frequency tables, and the Stanford Self-Efficacy for Managing Chronic Diseases Scale. Demographic data and the impact on self-management were cross-tabulated to identify the demographic characteristics of the targeted individuals and potential conditions with complications and highlight directions for future research.ResultsData from 152 participants showed that almost 1 in every 2 adults with chronic conditions was cybervictimized (69/152, 45.4%). Most victims (53/69, 77%) had disabilities; the relationship between cybervictimization and disability was statistically significant (P=.03). The most common means of contacting the victims was Facebook (43/68, 63%), followed by personal email or SMS text messaging, each accounting for 40% (27/68). Some participants (9/68, 13%) were victimized in web-based health forums. Furthermore, 61% (33/54) of victims reported that experiencing cybervictimization had affected their health condition self-management plan. The highest impact was on lifestyle changes such as exercise, diet, avoiding triggers, and avoiding excessive smoking and alcohol consumption. This was followed by changes to medications and follow-ups with health care professionals. Most victims (38/55, 69%) perceived a worsened self-efficacy on the Self-Efficacy for Managing Chronic Diseases Scale. Formal support was generally rated as poor, with only 25% (13/53) of victims having disclosed this experience to their physicians.ConclusionsCybervictimization of people with chronic conditions is a public health issue with worrying consequences. This triggered considerable fear and negatively influenced the self-management of different health conditions. Further context- and condition-specific research is needed. Global collaborations to address inconsistencies in research are recommended.