Background: The Social Support Questionnaire – Short Form (SSQ-6) is a widely used instrument that assesses availability and satisfaction of a person’s social support. The present study aimed to evaluate the construct validity and factor structure of the Spanish language version of the SSQ-6 during early pregnancy. Participants and methods: A total of 4,236 pregnant Peruvian women were interviewed at 10.3 ± 3.8 weeks of gestation. In-person interviewers were used to collect lifestyle, demographic, and social support characteristics. The construct validity and factorial structure of the SSQ-6 were assessed through exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The internal consistency was evaluated using Cronbach’s alpha. Results: The mean SSQ-6 score was 39.6 ± 6.8 and Cronbach’s alpha was 0.83. EFA resulted in a three-factor solution that accounted for 60.6% of the variance. CFA results confirmed the three-factor structure and yielded measures indicating goodness of fit (comparative fit index of 0.9401) and accuracy (root mean square error of approximation of 0.0394). Conclusion: Although the SSQ-6 was originally developed as a two-factor model, and previous studies have supported this, in our study a three-factor model was found to be more appropriate. The SSQ-6 was found to have good construct validity and reliability for assessing social support.