When it comes to choosing a turtleneck to match a blue suit, the most important thing is to choose a color that complements the suit. Some classic colors that will match well with a blue suit are white, gray, and black. These colors will create a clean and polished look. If you want to add some color to your outfit, you could also try wearing a turtleneck in a shade of blue that is similar to the color of your suit. This will create a cohesive and coordinated look. Ultimately, the best color for your turtleneck will depend on your personal style and the other colors in your outfit.