This book constitutes the proceedings of the 28th International Symposium on Graph Drawing and Network Visualization, GD 2021, which was held in Tübingen, Germany, during September 14-17, 2021. The 23 full papers and 5 short papers presented in these proceedings were carefully reviewed and selected from 74 submissions. The abstracts of 13 posters presented at the conference can be found in the back matter of the volume. The contributions were organized in topical sections as follows: Best Paper (Track 1: Combinatorial and Algorithmic Aspects); Best Paper (Track 2: Experimental, Applied, and Network Visualization Aspects); Crossing Minimization and Beyond-Planarity; Morphing and Graph Abstraction; Geometric Constraints; Topological and Upward Drawings; Linear Layouts; Contact and Visibility Representations; Geometric Aspects in Graph Drawing; AI applications; and Graph Drawing Contest Report.