The study investigated the relationship between human capital development and employee productivity of beverages manufacturing firms in Port Harcourt. The cross-sectional survey research design was adopted as the research design for the study. One hundred and twenty-five (125) workers from 12 beverage manufacturing firms in Port Harcourt who participated in the study, constituted the population. The Krejcie and Morgan table was employed to derive a sample size (S) of 94 from the population size (N). Consequently, ninety-four (94) copies of the questionnaire were administered to the respondents and 91 (91) were retrieved and analyzed. Two hypotheses were tested using the Spearman Rank Order Correlation Coefficient at 0.05 level of significance, and the outcome showed that human capital development significant relates correlates with employee productivity. Succession planning and employee motivation were found to boast employee productivity of beverage manufacturing firms in Port Harcourt. To this end, it was concluded that improving employee output requires a long-term investment in human capital development, which establishes a framework for greater operational dexterity and efficiency. Consequently, it was recommended that the management of beverage manufacturing firms should ensure that: employees, regardless of their assigned responsibilities, should have access to certain tools for improving their skills, as doing so has been found to encourage greater responsibility and accountability, leading to fewer instances of shifting blame when things go wrong; and their approach to human resource management and company culture should be such that fosters an atmosphere that encourages and facilitates high levels of employee motivation.