Background: The HER2-targeted antibody‒drug conjugate (ADC) is a novel approach for anti-HER2 treatment, and its efficacy in breast cancer patients has been demonstrated in clinical studies. However, the overall efficacy and safety of the various HER2-targeted ADCs in patients with gastric and gastroesophageal junction cancer has not been reported. Method: The PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL) and ClinicalTrials.gov databases were systematically searched. We assessed the quality of the included studies and then/span>extracted the overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS) to conduct the meta-analysis. Furthermore, we performed subgroup and sensitivity analyses to explore the sources of heterogeneity. The MINORS and RoB2 were used to assess the quality of the included studies, and STATA 17.0 software was used for data analysis. Results: Six single-arm studies and 2 randomized controlled trials (RCTs) with a total of 871 patients were included. The pooled ORR and DCR were 29% (95% CI: 20%-38%) and 71% (95% CI: 56%-86%), respectively. The pooled mOS and mPFS were 9.68 months (95% CI: 7.78-11.58 months) and 5.60 months (95% CI: 4.59-6.61 months), respectively. The incidence rates of all-grade adverse events (AEs) and grade≥3 AEs were 98.8% and 58.8%, respectively (95% CI: 43.0%-74.5%). Conclusion: HER2-targeted ADCs showed great survival benefits in GC/GEJC patients as second- and later-line treatments. However, the relatively high incidence of grade≥3 AEs needs to be considered.