Health behaviors such as physical activity (PA) are socially influenced, such that individuals from shared social networks or living environments may exhibit similar habits. This cross-sectional study examined associations of social support, social control, and family member stage of change with moderate-to-vigorous self-reported and objective PA in dyads of adult Hispanic family members. We used the Godin Leisure-Time Physical Activity Questionnaire to assess self-reported PA and accelerometry for objective PA. Validated scales assessed social support, social control, and stage of change. We performed multivariable multilevel analysis using generalized estimating equations (GEE) to account for within-dyad correlations. We conducted multivariable negative binomial regression for Metabolic Equivalent Task minutes (MET-minutes) (self-reported; N = 429) and accelerometer data (N = 356) and logistic regression for meeting PA guidelines (self-reported; N = 429). Most dyads were spouses (41%) or parents and adult children (32%). Individuals with high family support had 81% higher odds of meeting PA guidelines (1.81 adjusted odds ratio (aOR); 95% confidence interval [CI] = [1.06, 3.09]; p = .030) and 58% higher leisure-time MET-minutes of PA per week (1.58 adjusted incidence rate ratio [aIRR], 95% CI = [1.30, 1.91]; p < .0001) than those with low levels of support. Participants reporting medium-to-high family punishment were 98% higher in odds of meeting PA guidelines (1.98 aOR; 95% CI = [1.09, 3.61]; p = .025) and had 70% higher leisure-time MET-minutes of PA (1.7 aIRR; 95% CI = [1.36, 2.13]; p<.0001) compared with those with low scores. Participants with study partners in action or maintenance stages had significantly higher leisure-time MET-minutes of PA per week (aIRR = 1.45, 95% CI = [1.10, 1.91], p = .009 and aIRR = 1.33, 95% CI = [1.01, 1.76], p = .041, respectively) compared with those with partners in other stages. No statistically significant associations were observed for social control with any measure of PA or between psychosocial measures and accelerometer-assessed PA. Our findings demonstrated that interventions should engage social networks and multimodal forms of PA assessment to optimize behavior change in similar populations.