Abstract: We introduce a new neural network architecture, Multimodal Neural Graph Memory Networks (MN-GMN), for visual question answering. Our novel approach uses graph structure with different region features as node attributes and applies a recently proposed powerful graph neural network model, Graph Network (GN), to reason about objects and their interactions in the scene context. The input module of the MN-GMN generates a set of visual features plus a set of region-grounded captions (RGCs) for the image. The RGCs capture object attributes and their relationships. Two GNs are constructed from the input module using visual features and RGCs. Each node of the GNs iteratively computes a question-guided contextualized representation of the visual/textual information assigned to it. To combine the information from both GNs, each node writes the updated representations to an external spatial memory. The final states of the memory cells are fed into an answer module to predict an answer. Experiments show that MN-GMN rivals the state-of-the-art models on the Visual7W, VQA-v2.0, and CLEVR datasets.