Abstract Chlamydia trachomatis (CT), the leading cause of bacterial sexually transmitted diseases, is of public health significance because it causes considerable morbidity and socioeconomic burden worldwide. The quest for vaccine development against this pathogen has escalated to reduce its occurrence and global economic burden. Recently nanovaccines have emerged as attractive therapeutics due to flexibility in their formulation, biocompatibility and adjuvant properties. We have developed a nanovaccine against CT employing its MOMP (major outer membrane protein) and encapsulating it in PLGA [poly (D, L-lactic-co-glycolic acid) 85/15 nanoparticles. We hypothesized that encapsulated MOMP will be effective in activating dendritic cells (DCs) for induction of Th1 immune responses, which are needed for protection against CT. Exposure of mouse DCs to encapsulated MOMP at concentrations of 0.01 to 1 μg/mL revealed marked IL-6 and IL-12p40 secretions, with the latter being 20-fold more abundant. Encapsulated MOMP induced lower IL-10 and TNF levels with an elevated IL-12p40/IL-10 ratio, suggesting a predominant Th1 response. Time-kinetics studies (4 to 96 hr) showed increasing IL-12p40 concomitant with decreasing IL-10 concentrations. Analyses of CD11c+ DCs by FACS indicated heightened expression of the co-stimulatory molecules, CD80, CD86 and CD40 in response to encapsulated MOMP stimulation. TaqMan qPCR for mRNA transcripts validated the upregulation of TLR-2, CD80, CD86 and particularly CD40, which are important for adaptive immune responses. Our data suggest that encapsulated MOMP is a potential nanovaccine candidate by triggering enhanced co-stimulatory molecules and Th1 responses, which are required to protect against CT.