IGD may stand for:

• Internet Gateway Device Protocol as defined in UPnP
• Ilerici Gençler Dernegi, Progressive Young Association of Turkey
• Immunoglobulin D, an antibody protein involved in the maturation of B cells
• Integrated Graphics Device, a graphics processing unit integrated directly into the motherboard of a PC

Immunoglobulin D (IgD) is an antibody isotype that makes up about 1% of proteins in the plasma membranes of mature B-lymphocytes where it is usually coexpressed with another cell surface antibody called IgM. IgD is also produced in a secreted form that is found in very small amounts in blood serum, representing 0.25% of immunoglobulins in serum. Relative molecular mass and half-life of sIgD is 185 kDa and 2.8 days, respectively. Secreted IgD is produced as a monomeric antibody with two heavy chains of the delta (d) class, and two Ig light chains.