Gordon Royle's Open Questions
Colouring, algebraic graph theory, geometries.
Graph Coloring Problems
Archive for the book "Graph Coloring Problems" by Tommy R. Jensen and Bjarne Toft (Wiley Interscience 1995), dedicated to Paul Erdös. Gives progress and new problems.
Graph Theory Open Problems
Six problems suitable for undergraduate research projects.
Open Problems in Graph Algorithms
Compiled by Jerry Spinrad.
Past Open Problems Columns
By Douglas B. West, from the SIAM Activity Group Newsletter in Discrete Mathematics.
Perfect Graphs
Conjectures and open problems, maintained at the AIM.
Perfect Problems
Unsolved problems on perfect graphs.
Problem of the Month
Research problems collected by Bojan Mohar.
Problems in Signed, Gain, and Biased Graphs
Compiled by Thomas Zaslavsky.
Problems in Topological Graph Theory
Web text by Dan Archdeacon with a list of open questions in topological graph theory.
Some Open Problems
Open problems and conjectures concerning the determination of properties of families of graphs.
Some Open Problems in Graph Theory
Open Problems involving Steiner distance.
Three for the Money: The Degree/Diameter Problem
Students can understand and work on an unsolved problem in mathematics.
Unsolved Problems
Including the list of 50 problems of Bondy and Murty with current status. Compiled by Stephen C. Locke.