The main goal of management teams is to obtain the best possible results, seeking to use the available resources in the most efficient way, leading to continuous improvements in their processes. In this way, it is essential that companies focus on making good plans for their activities, organizing themselves internally to guarantee the best service or product, and seeking, as mentioned, the maximization of results and the guarantee of the company’s sustainability in the short and long term. Nowadays, companies face countless difficulties to enter the market, maintain quotas, and win new customers, and competition has become increasingly strong and diversified, the result of several factors such as globalization and the massification of technology as an important part of the transactional world. Operational management and all the other activities that interact with it within the company, as well as its image to the outside, are very important factors in the management of organizations. Therefore, companies must implement short-term financial management strategies that ensure favourable profitability and liquidity ratios, allowing them to fulfil their obligations punctually. Companies have been seeking several alternatives to achieve profitability in a sustained manner, especially regarding their day-to-day operations, since at any moment an externality may alter the company’s operations and profitability, and it is essential to immediately understand where adjustments can and should be made. Even removing the externalities inherent to any company, it is not possible to state that any company is, at any given moment, at the peak of its efficiency and profitability. The main objective of this research is to understand the influence that operational management has on financial performance, as expressed by EBIDTA. We used time series panel data and the fixed effects model for a sample of 80 Portuguese small and medium enterprises between 2009 and 2018 for this purpose. The research’s results led us to conclude that certain short-term ratios strongly influence the EBITDA of Portuguese SMEs, revealing a negative relationship between the days of payables outstanding and EBITDA was positively correlated with the company’s size, general liquidity, and debt structure. However, there was no significant relationship between the days of receivables outstanding, days of inventory outstanding, cash conversion cycle, or debt-to-equity.