Objective We used global positioning system (GPS) derived indicators and ecological momentary assessment (EMA) to assess real-time relationships between life-space, mood, and social interactions among older adults with and without HIV. Methods Participants (People with HIV [PWH] n=54, HIV- n=34) completed smartphone-based EMA surveys assessing mood and social interactions four times/day for 14-days. Participants’ smartphones were GPS enabled. Mixed-effects models analyzed concurrent and lagged associations among life-space and mood. Results PWH spent more time at home (79% vs 70%, z=-2.08; p=.04) and reported lower mean happiness (3.2 vs 3.7; z=2.63; p=.007). More daily social interactions were associated with higher ratings of real-time happiness (b=0.12; t=5.61; p< 0.001). Prior day social interactions (b=0.15; t=7.3; p Conclusions Interventions targeting social interaction may help increase positive mood in isolated older adults.