GLM-RAG: Graph Language Models for Graph-Based Retrieval-Augmented Generation

Maya Arseven, Anette Frank, Beni Egressy, Johann Higl, Moritz Plenz


Abstract
Retrieval-augmented generation (RAG) over knowledge graphs requires retrievers that can effectively capture both graph structure and semantic information. Recent approaches have explored graph neural network (GNN)-based retrievers to model graph topology in multi-hop reasoning tasks. In parallel, graph language models (GLMs) have emerged as a promising paradigm that integrates graph reasoning and the semantic capabilities of language models. In this work, we introduce a GLM-based retriever and investigate the comparative strengths of GLM-based, GNN-based, and traditional vector-search-based retrievers in single- and multi-hop RAG settings, and with a particular focus on transferability to unseen domains. Our findings suggest that finetuned GLM retrievers generalize better out of domain, achieving SOTA on two multi-hop benchmarks. On in-domain multi-hop QA datasets they remain comparable to prior work, with promising scaling as parameters and subgraph coverage increase. GNN-based retrievers achieve higher graph coverage with an efficient training setup, whereas the vector-search baseline excels at single-hop datasets.
Anthology ID:
2026.aacl-long.204
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
4503–4532
Language:
URL:
https://aclanthology.org/2026.aacl-long.204/
DOI:
Bibkey:
Cite (ACL):
Maya Arseven, Anette Frank, Beni Egressy, Johann Higl, and Moritz Plenz. 2026. GLM-RAG: Graph Language Models for Graph-Based Retrieval-Augmented Generation. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 4503–4532, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
GLM-RAG: Graph Language Models for Graph-Based Retrieval-Augmented Generation (Arseven et al., AACL-IJCNLP 2026)
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PDF:
https://aclanthology.org/2026.aacl-long.204.pdf