Introduction: Gastroenteropancreatic neuroendocrine neoplasms (GEPNENs) are often diagnosed in an advanced stage. As the optimal sequence of therapy remains largely unclear, all treatment-related outcomes, including health-related quality of life (HRQoL) prospects, should be assessed according to patients' preferences. Methods: A targeted search was performed in PubMed and EMBASE to identify studies on treatment effect and HRQoL, measured using the EORTC QLQ-C30 tool, in patients with advanced, well-differentiated GEPNENs. Study quality was assessed, and meta-analyses were performed for global health status/QOL and tumour response. Results: The search yielded 1,322 records, and 20 studies were included, examining somatostatin analogues (SSA), peptide receptor radionuclide therapies (PRRT), chemotherapy, SSA-based combination therapies, and targeted therapies. Global HRQoL was stable, and rates for disease stabilisation were moderate to high across all treatments. Meta-analyses for global health status/QOL after SSA treatment were not significant (mean difference: –0.3 [95% CI: −1.3 to 0.7]). The highest pooled overall tumour response rate was 33% (95% CI: 24–45%) for PRRT. The highest pooled clinical benefit rate was 94% (95% CI: 65–99%) for chemotherapy. Conclusion: All treatments appeared beneficial for disease stabilisation while maintaining stable global health status/QOL. High-quality HRQoL reporting was lacking. HRQoL should be a central outcome next to well-established outcomes.