There have been no quantitative studies on dysphagia and its impact on quality of life (QOL) of adults with cerebral palsy (CP). In this cross-sectional study, we aimed to investigate the characteristics of dysphagia symptoms and their impact on QOL in adults with CP on a full oral diet compared with healthy adults. Additionally, we aimed to determine the factors affecting dysphagia-related QOL in this population. We enrolled adults with CP on full oral diet (N = 117) and healthy individuals (N = 117) and interviewed them using the swallowing-quality of life (SWAL-QOL) questionnaire which includes 14 items regarding dysphagia symptoms and 30 items regarding swallowing-related QOL. The functional status of each participant with CP was evaluated using the gross motor function classification system, the manual ability classification system (MACS), and the Functional Oral Intake Scale (FOIS). Among pharyngeal symptoms, choking on food was reported most frequently (sometimes or more 76.9%), followed by coughing and choking on liquid. Among oral symptoms, chewing problems were reported most frequently (sometimes or more 59.8%), followed by food dribbling from the mouth (sometimes or more 53.8%). Compared to healthy adults, those with CP reported worse QOL across all SWAL-QOL items, with the lowest scores obtained for meal duration, followed by communication, burden, fatigue, sleep, and eating desire. On multiple linear regression analysis, higher MACS level, lower FOIS level, and older age were predictors of worse SWAL-QOL score. Among adults with CP, it is necessary to evaluate swallowing function and establish an active intervention plan even if a full oral diet is established.