An increasing number of companies are setting up Project Management Offices (PMOs) to benefit from project portfolio management and enhance their overall competitiveness in the market. However, it is never ending process of encountering challenges and identifying areas for improvement. This paper aims to apply Project Management Maturity Models (PMMMs) as a tool to assess the level of maturity in portfolio management in different project management knowledge areas. Specifically, this paper examines a selected case study from the Transport & Logistics industry, utilizing findings to propose strategies for improving process performances. Findings show that there are valuable benefits in setting up of PMO in the Transport & Logistics industry and that the PMMMsm model is applicable in this specific industry. Finally, the paper enriches the existing literature in the field, but also provides strategies for practitioners looking to improve project performance through PMOs, especially in the Transport & Logistics industry.