The Nigerian healthcare industry is bedevilled with infrastructural dilapidations and a dysfunctional healthcare system. This study investigated the influence of healthcare professionals’ well-being and quality of work-life (QoWL) on the quality of care (QoC) of patients in Nigeria. A multicentre cross-sectional study was conducted at four tertiary healthcare institutions in southwest, Nigeria. Participants’ demographic information, well-being, quality of life (QoL), QoWL, and QoC were obtained using four standardised questionnaires. Data were summarised using descriptive statistics. Inferential statistics included Chi-square, Pearson’s correlation, independent samples t-test, confirmatory factor analyses and structural equation model. Medical practitioners (n = 609) and nurses (n = 570) constituted 74.6% of all the healthcare professionals with physiotherapists, pharmacists, and medical laboratory scientists constituting 25.4%. The mean (SD) participants’ well-being = 71.65% (14.65), QoL = 61.8% (21.31), QoWL = 65.73% (10.52) and QoC = 70.14% (12.77). Participants’ QoL had a significant negative correlation with QoC while well-being and quality of work-life had a significant positive correlation with QoC. We concluded that healthcare professionals’ well-being and QoWL are important factors that influence the QoC rendered to patients. Healthcare policymakers in Nigeria should ensure improved work-related factors and the well-being of healthcare professionals to ensure good QoC for patients.