This study investigates the impact of cybersecurity practices on the quality of accounting information systems, focusing on Portuguese small and medium-sized enterprises. It examines how external integration, cybersecurity countermeasures, knowledge of policies, and self-reported behaviours influence the quality of accounting information systems. This study employed a survey-based approach, specifically targeting employees within the accounting and finance departments of Portuguese SMEs, and an empirical analysis using regression models on survey data. Findings demonstrate that cybersecurity countermeasures and self-reported behaviours significantly enhance the quality of accounting information systems, while external integration and knowledge of policies show mixed impacts. A balanced approach combining technical and behavioural measures is essential. The study highlights Portuguese small and medium-sized enterprises unique challenges in aligning cybersecurity practices with operational constraints, offering actionable insights for improving cybersecurity resilience and the integrity of accounting systems.