Background: The Fundamentals of Care framework emphasizes a patient-centered approach that prioritizes the nurse–patient relationship and care environment to meet patients’ basic needs, including oral hygiene. Recognized as crucial for preventing systemic health problems, oral care neglect is a global concern. Studies identify missed oral care as a widespread issue, contributing to significant patient safety risks. This study aimed at measuring missed nursing care occurrence in a Northern Italian university hospital, exploring the association between missed oral care with nursing staff characteristics and oral care policies. Methods: A single-center cross-sectional study was conducted according to the STROBE guidelines. Data collection was performed in May 2022 using the MISSCARE survey, a self-administered questionnaire sent by email to 473 nurses from all inpatient units. The degree of implementation of oral care policies was obtained by accessing the Facility Score Sheet data at the department level. Descriptive statistics, chi-square tests, and Fisher tests were conducted using SAS 9.4 and R software. Results: Providing oral care was the third-most missed nursing care after rotating patients every two hours and walking them three times daily. The reasons for missed care included resource shortage and high patient turnover. The Facility Score Sheet data showed a low adoption of oral care policies. No significant associations were found between missed oral care and both nurses’ characteristics and oral care policy at the department level. Conclusions: The study confirms highly missed oral care in acute care settings, emphasizing the urgent need for systemic changes via an evidence-based oral care policy and practice implementation. This study was prospectively registered under protocol 293 CE 050/2022 (8 Aril 2022).