Background: Knee osteoarthritis (OA) affects mostly older adults and its primary risk factor is obesity. This study sought to understand weight-control strategies, facilitators of and barriers toward weight control in older adults with knee OA who preferred not to undergo physician-recommended total knee arthroplasty. Methods: For this qualitative descriptive study, older outpatients (N = 118) were recruited from orthopedic clinics at three hospitals. Data were collected through face-to face, individual in-depth interviews using a semi-structured interview guide and analyzed using content analysis. Results: Among participants, only 25.4% had body weight in the normal range and 55.9% reported having controlled their weight. Their most common weight-control strategies were to control diet and to exercise and control diet together. Weight control was facilitated by desiring good health, wanting to improve walking or movement, perceiving that they had gained weight, wanting to look good, and advice from healthcare providers. Common barriers to participants' weight control were perceiving that dietary control was not needed, controlling appetite was difficult, dietary control was difficult, and not eating was physically uncomfortable. Conclusions: Our findings help healthcare providers understand how older adults with knee OA perceive weight control and serve as a reference for developing weight-control programs. Health care providers can integrate these identified facilitators and barriers into a weight-control intervention program. The importance of weighing oneself every day, the meaning of body mass index, consulting with a dietician regularly to control weight, and providing appropriate knowledge about aging and weight control should also be included in any weight-control intervention program.