The flag of Guam has an aspect ratio of 22:41. It consists of two main colors: a deep blue background (Pantone 286 C) and a red border (Pantone 186 C). The red border is 1/8 the width of the flag on all four sides.

At the center of the flag, there's an elliptical shape containing a slingshot stone known as "Hagåtña Stone" and a coconut palm tree. The length of the ellipse is 2/3 the length of the flag, and the width of the ellipse is 1/2 the width of the flag. The ellipse is centered both horizontally and vertically on the blue field.

The Hagåtña Stone and the coconut palm tree are depicted in brown (Pantone 469 C) and green (Pantone 356 C) colors, respectively.