Abstract: A snap-on cross brace is easily coupled to, and removed from, spaced-apart structural members of the type used in the assembly of docks, decks, and scaffolds. With respect to a structure having first and second spaced-apart support members, each with an outer diameter, a cross brace according to the invention comprises an elongate member having two ends spaced apart at a distance greater than the spacing of the support members, and first and second swiveling snap-on elements, one disposed at a respective one of the two ends of the elongate member. Each snap-on element having a c-shaped cross section with an inner diameter slightly less than the outer diameter of the support members, such that each snap-on element may be oriented over a respective one of the support members and engaged at different heights through the application of pressure fixing the elongate member at an angle therebetween.