Gene and vaccine delivery offer promising technologies for the treatment of several diseases. However, they suffer from low transfection efficacy, enzyme degradation, and immunogenicity of the gene-based therapeutic agents or vaccines. Thus, several materials were reported as carriers for gene therapeutic agents. Alginates-based materials provide solutions for several challenges of other biomaterials. They exhibit high biocompatibility for many biological cells with low or minimal toxicity, show high stability under different environments, and can proceed quickly into various forms such as beads, capsules, fibers, and hydrogels. Bio-beads of calcium alginate is widely used to encapsulate gene-based therapeutic agents. They can be quickly processed as three-dimensional (3D) scaffolds, hydrogels, capsules, spheres, foams, sponges, and fibers. They can be used as carriers for gene and vaccine delivery. They offer several advantages, such as high biodegradability, good encapsulation efficiency, excellent biocompatibility, and good chelating capacity. The alginate-based system was used for gene delivery for tissue generation, bone generation, cartilage repair, and cancer therapy. Alginate-based biomaterials offered the development of gene-activated bio-inks (GABs) for 3D printing. This book chapter summarizes the applications of alginate as carriers for gene and vaccine delivery.