Background and Aim: Data on oral health of the elderly are uncommon in the South-South region of Nigeria. The purpose of this research was to find the relationship between dental caries and oral health knowledge, attitude, behavior, and oral hygiene status of the pensioners in Port Harcourt, Rivers State. Materials and Methods: The research was a correlational study. A total of 543 pensioners were selected by systematic random sampling. Data were collected with a self-developed Oral Health Assessment Questionnaire designed in five sections (A-E) and analyzed using SPSS version 20 (IBM SPSS Armonk, New York, USA). Relationship between variables was established using simple and multiple regressions. Significance was determined at 0.05 alpha level. Results: The mean knowledge, attitude, and behavior scores were 12.23, 27.61, and 8.76, respectively. Whereas oral health knowledge accounted for 11.56% (R2 = 0.1156) of the variance in the pensioners' dental caries status, oral health attitude and behavior, respectively, accounted for 39.69% (R2 = 0.3969) and 27.04% (R2 = 0.2704) of the variance in the pensioners' dental caries status. Oral hygiene accounted for 33.64% (R2 = 0.3364) of the variances in the dental caries status of the pensioners. Conclusion: This study found a low and negative nonsignificant correlation between dental caries and oral health knowledge, a moderate and negative nonsignificant correlation between dental caries and oral health attitude, and a moderate and negative significant correlation between oral health behavior and dental caries. Similarly, oral hygiene level of the pensioners was moderately and significantly correlated to dental caries.