Petroleum-producing companies in Nigeria were forced to increase spending on Nigerian-sourced materials and services from $8 billion to $13 billion since 2010, due to the Nigerian Oil and Gas Industry Content Development Act that was implemented in 2010 to support local firms and improve the companies’ performance. There is sparse research on how the act affected the companies’ performance. This descriptive correlational study addressed the gap in the literature. Survey data from 372 employees of the five major petroleum-producing companies in Nigeria was analyzed. The study results indicated that the act had a positive effect on the employees’ internal competence factor and the organizations’ operational performance factor. The results are significant in understanding the impact of the act on performance.