Biodegradable polyanhydride nanoparticles have been used as vaccine adjuvants and delivery vehicles. Upon parenteral administration, the surface characteristics of these nanoparticles may be modified by serum protein adsorption, likely affecting how the particles interact with antigen presenting cells. These studies investigated the role of the differential adsorption of serum proteins onto carbohydrate-functionalized and non-functionalized polyanhydride nanoparticles of different chemistries on interactions with dendritic cells (DCs). Di-mannose (a carboxymethyl-modified disaccharide of 1,2-alpha-linked-D-mannopyranoside) or glycolic acid was covalently linked to nanoparticles synthesized using copolymers of 1,6-bis(p-carboxyphenoxy) hexane (CPH) and sebacic acid (SA) and 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane (CPTEG) and CPH. Serum protein adsorption to CPH: SA nanoparticles enhanced particle internalization, but did not enhance uptake of CPTEG: CPH nanoparticles. When DCs were cultured with nanoparticles, the surface expression of MHC II, CD86, and CD206 was enhanced and mediated by both polymer chemistry and functionalization. Cytokine secretion by DCs was differentially modulated by both polymer chemistry and functionalization. The amount and profile of serum proteins adsorbed indicated that polymer hydrophobicity and functionalization enhanced protein adsorption. Overall polymer chemistry, functionalization, and serum protein adsorption influenced nanoparticle interactions with DCs and elucidating the complex relationships between these parameters and dendritic cell maturation will enable rational design of targeted vaccines and immunotherapies.