Background: As people age, they are more likely to face financial, medical, and mobility related challenges that can put them at risk of food insecurity. This is a serious public health concern that has been associated with many adverse health outcomes.Objectives: This study examined factors associated with food insecurity among older adults who receive congregate meals from the Administration on Aging’s Nutrition Services Program. Combining participant, geographic, and provider data allowed for a more detailed assessment of older adult food insecurity than is typically possible using other national surveys. Design: A cross-sectional study. We conducted a cross-sectional data analysis using national survey data from the Administration on Aging’s Nutrition Services Program Outcomes Survey, conducted from 2015 to 2016. The data were linked to provider data from the meal site where participants ate. Logistic regression analysis was conducted to estimate the associations between food insecurity and demographic, household, geographic, and provider-level characteristics and circumstances. Setting: Interviews with congregate meal participants were conducted in person at congregate meal sites or another preferred place. Participants: A total of 520 older adults were included as study participants. All older adults were participating in the Nutrition Services Program and receiving congregate meals at the time of the survey interview. All participants were at least 67 years old. Measurements: This study used a 6-item food security measure as the dependent variable. Older adults who answered at least 3 of the 6 questions affirmatively were considered food insecure. Food security was assessed over a 30-day recall period. Results: 18% of congregate meal participants lived in food insecure households. Among congregate meal participants, having low income, difficulty reaching family and friends, past military service, and mobility challenges, and attending a site that provided nutrition counseling were associated with increased food insecurity (most odds ratios ranged from 1.1 to 2.6). Older age, geographic access to food, certain chronic health conditions, and provider-offered nutrition screening and social activities reduced the odds of experiencing food insecurity (most odds ratios ranged from 0.2 to 0.4). Conclusions: Although the Nutrition Services Program helps to alleviate food insecurity, a nontrivial percentage of participants remain food insecure. Nutrition programs can help address clients’ food access limitations by broadening nutrition screenings at meal sites to include more comprehensive assessments based on non-traditional risk factors for food insecurity.