Background: Patients with multiple myeloma (MM) are at an elevated risk of venous thromboembolism (VTE), which is further increased in patients receiving immunomodulatory drugs (IMiDs). Current guidelines suggest that non-vitamin K oral anticoagulants (NOACs) may be an alternative to low-dose aspirin (ASA) for primary thromboprophylaxis in this population. However, there is limited data comparing these two antithrombotic therapies among MM patients undergoing treatment with IMiDs. Methods: We performed a systematic review and meta-analysis to compare NOACs with ASA for primary thromboprophylaxis in individuals with newly-diagnosed or relapsed/refractory MM undergoing outpatient chemotherapy with an IMiD-based regimen. PubMed, Cochrane, and EMBASE were systematically searched from inception to January 2023. Observational studies and randomized controlled trials were included when comparing NOACs versus aspirin for thrombotic and hemorrhagic outcomes. Statistical analysis was performed with Review Manager 5.4.1. Results: We included 10 randomized controlled trials and observational studies comprising 1026 MM patients who underwent primary thromboprophylaxis with NOACs (33%) or ASA (67%). Thromboprophylaxis with NOACs was associated with a significantly lower incidence of VTE compared with ASA (OR, 0.33; 95% CI, 0.16-0.68; p < 0.001; I² = 0%). Each group had one major bleeding event, with no statistically significant difference between NOACs and ASA (OR, 1.35; 95% CI, 0.05-35.51; p = 0.86; I² = 51%). Similarly, clinically relevant non-major bleeding (OR, 0.56; 95% CI, 0.12-2.70; p = 0.47; I² = 0%) and minor bleeding (OR 1.48; 95% CI: 0.42-5.24; p = 0.54; I² = 0%) event rates did not differ significantly between groups. Conclusions: These findings suggest that NOACs may be superior to ASA for VTE prophylaxis among MM patients receiving IMiD-based chemotherapy, with no significant difference in the overall bleeding risk between the two groups.