Green and orange combine to become brown. According to Color Matters, both green and orange are secondary colours, which are created by combining two basic colours. Brown is the result of combining any two secondary hues, ranging from muddy brown to olive brown.
The precise shade of brown produced by mixing green and orange relies on the hues of green and orange. While light hues produce a light, yellowish brown, dark colours produce a darker, more olive brown. Blending green or orange with a primary colour may produce a tertiary colour, but mixing the two secondary colours always produces brown, regardless of hue or saturation.