Physical inactivity is a vital risk factor for the development and maintenance of chronic ill-health conditions among older adults. This study examined personal factors associated with physical activity (PA) behavior of urban-dwelling older adults in Sri Lanka, a middle-income country in South Asia. A total of 880 older adults (aged ≥60 years) participated in this cross-sectional study. They responded to anthropometrical, health, and socio-demographic data pertaining to their current physical and behavioral status. The mean age of the participants was 70.1 years ( ±6.0), and the majority (75%) were women. Increasing age, male gender, middle income, having cardiovascular diseases or arthritis, deficiencies in muscle strength and balance, pain, and lower self-rated health were associated with insufficient PA behavior among the participants. Old-age physical activity promotion programs should target older adults in advanced ages and men in particularly, as they are highly vulnerable to sedentary lifestyles. Muscle strength and balance, a neglected area in PA promotion in older adults, seem to play an important role in older adults' participation in physical activities. Incorporation of pain management, and muscle strength and balance techniques into older adults' PA promotion programs would probably increase adherence rates of the participants in such programs.