Although the Gerontological Personality Disorders Scale (GPS) can aid in detecting personality disorders (PDs) in older adults in general practice, its availability does not guarantee its use. This study therefore aimed to examine the feasibility and acceptability of the GPS from an older adult, informant, and professional perspective. A convergent parallel mixed methods study was conducted. Qualitative data were collected through semistructured interviews with four general practitioners and four nurse practitioners and were analyzed thematically. Quantitative data were collected through a 5-item questionnaire completed by 329 older adults and 329 informants. The thematic analysis revealed five major themes regarding feasibility and acceptability according to the professionals: taboo to ask intimate questions, quite unfamiliar with these disorders, assets, PDs are a topic of interest in general practice, and preconditions. Descriptive statistics showed that most older adults and informants found the GPS items to be clearly phrased, easy to understand, and nonconfrontational or not unpleasant to answer. The GPS is a feasible and acceptable instrument for detecting PDs in older adults in general practice. Educating professionals about PDs in older adults and the GPS is important prior to its use in daily practice and might further increase its acceptability.