Multimodal pain control can be beneficial in relieving postoperative pain and limiting narcotic use following orthopedic procedures. Additionally, with increasing interest in outpatient arthroplasty procedures, providers have interest in adequate early postoperative pain control and complications. The purpose of this study was to investigate the effect of dexamethasone on pain, postoperative nausea and vomiting, and length of stay following total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RTSA). One hundred twelve patients undergoing TSA or RTSA by a single surgeon were assessed for inclusion in this investigation. We performed a prospective randomized controlled trial to investigate the effect of 10 mg of dexamethasone administered within 90 minutes of surgery. Primary outcome assessed was the average morphine equivalent use over the first 24 hours postsurgery. Secondary outcomes included postoperative visual analog scale (VAS) scores, antiemetic use, postoperative nausea and vomiting, and complications. A total of 75 patients were included in the final analysis, with 32 patients (42.7%) randomized to the control group and 43 (57.3%) randomized to the dexamethasone group. Body mass index was significantly greater in the control group (33.8 vs. 30.3, P = .014); otherwise, there were no significant demographic differences between groups. Average ondansetron use was significantly lower in the dexamethasone group compared with controls for the 0- to 4-hour interval (0.1 vs. 0.9 mg, respectively, P = .006) and was lower overall for the first 24 hours (0.3 vs. 1.0 mg, P = .025). Differences in VAS scores were significantly lower in the dexamethasone group at all time points (P < .05 for all). The average VAS score over the 24-hour period for the dexamethasone group was also significantly lower than the controls (3 vs. 6, P < .001). Morphine equivalent use was significantly lower in the dexamethasone group compared with controls at 12-16 hours (1.7 vs. 4.0 mg, respectively, P = .004) and at 16-20 hours (1.7 vs. 3.4 mg, respectively, P = .006). When averaged over the first 24 hours, morphine equivalent was also significantly lower in the dexamethasone group (16.1 vs. 25.4 mg, P = .007). There was no significant difference in glucose control or complications between groups. Dexamethasone decreases opioid requirements in the first 24 hours following surgery, provides improved pain control, and decreases antiemetic use following shoulder arthroplasty. Dexamethasone is an important multimodal adjunct for controlling pain and postoperative nausea and vomiting following primary TSA.