The retail industry is currently facing increasingly intense competition, requiring optimal supply chain efficiency. Warehouses play a strategic role in controlling inventory flows and supporting a company’s operational performance. At K3Mart, stock shortages are still frequently found, caused by low supplier compliance with Service Level Agreements (SLA) and delays in delivery schedules, which negatively affect distribution processes and store service quality. This study aims to analyze the effect of supplier compliance with SLA and delivery timeliness on warehouse operational performance at K3Mart. This research employs a quantitative method by distributing questionnaires to 40 respondents from the warehouse, purchasing, and procurement divisions using a saturated sampling technique. The research instrument uses a Likert scale. Data analysis was conducted using validity and reliability tests, classical assumption tests, multiple linear regression analysis, t-test, F-test, and coefficient of determination with the assistance of SPSS software. The results show that supplier compliance with SLA and delivery timeliness have a positive and significant effect, both partially and simultaneously, on warehouse operational performance. Therefore, improving supplier compliance with SLA and delivery timeliness can enhance optimal warehouse operational performance.