Introduction: Adherence to Clinical Practice Guidelines for sepsis can improve care processes and outcomes; however, sepsis guideline adherence is plagued by many barriers. The purpose of this article is to report the perceived barriers for implementing a sepsis guideline at British Columbia's Children Hospital. Methods: This is a mixed method study. Data were collected from clinicians using a questionnaire that covered 3 major domains and included two open-ended questions. Quantitative data analysis focused on the Mean Overall Barrier Score (MOBS) in each category using descriptive and inferential statistical techniques. Qualitative data were analyzed thematically through deductive and inductive approaches. Results: A total of 176 clinicians participated in the study. Nurses and physicians were the largest groups of participants (52.7% and 41.2%, respectively). Nurses perceived more barriers (MOBS: 3.3; 95% CI: 3.1-3.4) compared to attending physicians (MOBS: 3.6; 95% CI: 3.3-3.8). The most frequent type of barriers reported was contextual, including environmental and guideline related barriers (MOBS: 3.1; 95% CI: 2.9-3.3), whereas the least barrier reported was lack of motivation (MOBS: 4.0; 95% CI: 3.9-4.2). Clinicians who were highly motivated and perceived less environmental barriers were more likely to use the guideline (Odds Ratio of 2.2 [p = .036] and 2.2 [p = .092], respectively). Conclusions: Motivation was the most important predictor of guideline use while contextual barriers hindered use. Therefore, motivating the clinicians and removing external barriers offers the best chance for successful guideline implementation. Furthermore, removing barriers for the use of sepsis guideline among nursing group needs more consideration.