The amount of plasma pentraxin 3 (PTX3) is gradually being considered as a novel biomarker in forecasting poor clinical outcomes in patients with coronary artery disease (CAD). However, very little is known about the connection between PTX3 and CAD. This dose–response meta-analysis was carried out to quantify the relationship between circulating PTX3 concentration and CAD prognosis. A systematic literature search was conducted using PubMed, EuropePMC, ProQuest, EBSCOhost, SCOPUS, Cochrane Library, and Google Scholar up until April 2021. The primary outcome of this study consisted of mortality and major adverse cardiovascular events (MACEs). The current meta-analysis comprised 15 studies with a total of 11.365 participants. High circulating PTX3 concentrations were associated with a higher risk of composite poor outcomes as compared to low circulating PTX3 concentrations (OR: 1.36 [1.18, 1.54], p < 0.001; I2 = 86.69%, Pheterogeneity<0.001), mortality (OR: 1.43 [1.15, 1.71], p < 0.001; I2 = 87.58%, Pheterogeneity<0.001), and MACEs (OR: 1.28 [1.08, 1.48], p < 0.001; I2 = 35.86%, Pheterogeneity = 0.08) in patients with CAD. Consistent results were obtained during meta-regression analyses and in all examined subgroups. The adjusted odds ratios (aORs) for composite poor outcomes increased by 32% per 1 ng/mL increment (OR: 1.32 [1.21, 1.43]) in line with the dose–response meta-analysis. A significant positive dose-dependent association between circulating PTX3 concentration and the risk of poor outcomes in patients with CAD was found in this dose–response meta-analysis.