This systematic review and meta-analysis assesses the effectiveness of no or low-dose versus high-dose aspirin on the incidence of coronary artery aneurysms (CAAs), intravenous immunoglobulin (IVIG) resistance, hospital stay length, and fever duration during the acute phase of Kawasaki disease. Our review adheres to the Preferred Reporting Items for Systematic Reviews guidelines. The PubMed and Google Scholar databases were comprehensively searched to identify relevant studies in the literature, including observational studies and randomized controlled trials (RCTs). The primary outcome was the incidence of CAAs. The secondary outcomes were the hospital stay length, fever duration, and IVIG resistance. The risk of bias was assessed using the Newcastle–Ottawa scale for cohort studies and Cochrane’s Risk of Bias Tool for RCTs. The data were analyzed using the Review Manager software. Twelve studies with a total of 68,495 participants met the inclusion criteria. The incidences of CAAs (odds ratio [OR] = 0.93; 95% confidence interval [CI] = 0.64–1.34) and IVIG resistance (OR = 1.46; 95% CI = 1.00–2.12) did not differ significantly between no or low-dose versus high-dose aspirin in treating acute KD. Moreover, the fever durations (mean difference [MD] = 3.55 h; 95% CI = −7.99–15.10) and hospital stay lengths (MD = −0.54 days; 95% CI = −2.50–1.41) were similar in the no and low-dose aspirin group compared to the high-dose aspirin group. Our review indicates that there are no significant differences in the incidences of CAA and IVIG resistance, fever durations, and hospital stay lengths between no or low-dose versus high-dose aspirin in treating the acute phase of KD.