Background: Depression is a prevalent mental health condition among older adults and may be linked to multiple systemic and functional factors. Emerging evidence suggests a bidirectional relationship between depressive symptoms and poor oral health, but data from European populations remain scarce. Methods: A cross-sectional study was conducted in 181 community-dwelling adults aged over 66 years in Madrid, Spain. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS-15), and functional dependence using the Barthel Index. Oral examinations included the number of caries, root remnants, and gingivitis. Additional variables included the Body Mass Index (BMI), smoking and alcohol consumption, and medication use. Data were analysed using descriptive and non-parametric statistics. Results: Overall, 49.2% of participants exhibited depressive symptoms (34.8% moderate, 14.4% severe). Old age and excess weight were significantly associated with depression (p < 0.05). Depressed participants showed higher functional dependence scores on the Barthel Index (p < 0.001). Oral health indicators, including higher number of caries, root remnants, and gingivitis, were significantly worse among those with depression (p < 0.005). Oral hygiene practices such as toothbrushing were slightly more frequent in the non-depressed group, while oral irrigator use was low across all groups. Conclusions: Depressive symptoms in older Spanish adults were associated with poorer oral health, greater functional dependence, and certain clinical factors such as BMI and antidepressant use. These findings highlight the importance of integrated, multidisciplinary approaches to promote both mental and oral health in ageing populations. Longitudinal studies are warranted to clarify the causal pathways underlying these associations.