This study examines the effect of cost accounting information on profit planning in Nigerian oil and gas firms. Profit planning, encompassing budgetary profit forecasting and performance evaluation and profit optimization, is critical for organizational sustainability in the highly capital-intensive and volatile oil and gas sector. The study specifically investigates how the dimensions of cost accounting information cost control information and cost allocation and analysis information influence profit planning outcomes. A descriptive and explanatory research design was adopted, targeting managerial and accounting staff across 50 registered oil and gas firms in Nigeria. Data were collected through structured questionnaires and analyzed using descriptive statistics and multiple regression analysis. The findings reveal that both cost control and cost allocation information have a positive and significant effect on budgetary profit forecasting and performance evaluation. The regression results indicate that cost accounting information explains a substantial proportion of the variance in profit planning, with cost control information exhibiting a slightly stronger influence. The study concludes that effective profit planning in Nigerian oil and gas firms is heavily dependent on the availability, accuracy, and utilization of cost accounting information. It is recommended that firms strengthen their cost accounting systems, enhance managerial capacity, adopt modern technology, and integrate cost data into strategic decision-making processes. This will enable firms to improve financial performance, optimize resource utilization, and sustain profitability in a highly competitive industry.