Introduction Chest infections following acute stroke contribute to increased morbidity and mortality. We aimed to investigate factors associated with chest infections that occur within 30 days of stroke, the impact on 90-day survival, and the role of stroke unit care. Methods Patient-level data from the Australian Stroke Clinical Registry (2010–13; 23 Queensland hospitals), were linked with Queensland hospital admission, emergency department (ED), and national death registry data. Acute chest infections were determined using ICD-10 codes from the stroke admission, hospital readmissions, ED contacts, and cause of death data. Patients aged ≥18 years without a prior stroke or chronic respiratory condition were included. Multilevel (hospital and patient) multivariable regression and survival analysis were used to identify associated factors and the influence on 90-day survival. Results Overall, 3149 patients (77% ischemic stroke, 47% female, median age 74 years) were included; 3.1% developed a chest infection within 30 days. Associated factors included: admission to intensive care (OR: 8.26, 95% CI: 4.07, 16.76); and urinary tract infection (OR: 3.09, 95% CI: 1.89, 5.04). Patients not treated in stroke units had a two-fold greater odds of chest infections (OR: 1.96, 95% CI: 1.25, 3.05). Chest infection afforded a greater hazard of death at 90 days (HR: 1.42, 95% CI 1.04, 1.93). This was reduced for those admitted to a stroke unit (HR: 1.31, 95% CI 0.99, 1.75). Conclusion Results emphasize the need for active prevention and highlight the importance of stroke unit care in mitigating risk and improving survival in those with stroke-related chest infections.