Dexamethasone is increasingly used after total joint arthroplasty (TJA) to reduce postoperative nausea and vomiting (PONV) and pain. The primary aim of this study was to examine the relationship between perioperative intravenous (IV) dexamethasone and length of stay (LOS) in patients undergoing primary, elective TJA. All patients who underwent TJA from 2015 to 2020 and received perioperative IV dexamethasone were queried from the Premier Healthcare Database. The cohort of patients who received dexamethasone was randomly truncated by a power of 10 and matched in a 1:2 ratio based on age and sex to patients who did not receive dexamethasone. Patient characteristics, hospital factors, comorbidities, 90-day postoperative complications, LOS, and postoperative morphine milligram equivalents were recorded for each cohort. Univariate and multivariate analyses were conducted to assess differences. Overall, 190,974 matched patients were included, 63,658 (33.3%) of whom received dexamethasone and 127,316 (66.7%) did not. The dexamethasone cohort was composed of fewer patients with uncomplicated diabetes (11.6% vs. 17.5%, P < 0.001). Patients who received dexamethasone had significantly decreased mean LOS compared with patients who did not receive dexamethasone (1.66 vs. 2.03 days, P < 0.001). After controlling for confounding variables, dexamethasone was associated with significantly lower risk of pulmonary embolism (adjusted odds ratio [aOR]: 0.74, 95% CI: 0.61 to 0.90, P = 0.003), deep vein thrombosis (aOR: 0.78, 95% CI: 0.68 to 0.89, P < 0.001), PONV (aOR: 0.75, 95% CI: 0.70 to 0.80, P < 0.001), acute kidney injury (aOR: 0.82, 95% CI: 0.75 to 0.89, P < 0.001), and urinary tract infection (aOR: 0.77, 95% CI: 0.70 to 0.80, P < 0.001). In aggregate, dexamethasone was associated with similar postoperative opioid utilization between cohorts ( P = 0.061). Perioperative dexamethasone was associated with reduced LOS and decreased postoperative complications including PONV, pulmonary embolism, deep vein thrombosis, acute kidney injury, and urinary tract infection after TJA. Although perioperative dexamethasone was not associated with notable reductions in postoperative opioid utilization, this study supports the use of dexamethasone to decrease LOS through multifactorial mechanisms beyond decreased pain.