Galactomannans are nonionic polysaccharides structurally composed of residues of mannose and galactose, and they are mainly obtained from the seed endosperm of leguminous plants. In specific cases, galactomannans can be subjected to chemical, physical or biological modifications in order to reduce their thickening ability, increase solubility and insert charged groups. Among galactomannans, guar gum, locust bean gum, fenugreek gum and tara gum in their native or modified form are used as ingredients in food products but also as biomaterials because of their potential use as carriers of bioactive compounds. Different methods have been used to create delivery systems (spray drying, hydrogel, emulsion and coacervation) that contain native or modified galactomannans associated with other biopolymers that encapsulate different bioactive agents, such as dyes, vitamins, essential oils, peptides and enzymes. This minireview aims to present the main galactomannans and their modifications used in the encapsulation of bioactive compounds applied in food.