The present disclosure provides isolated monoclonal antibodies (e.g., humanized and human monoclonal antibodies), or antigen-binding fragments thereof, that specifically bind to human natural killer cell inhibitory receptor group 2A (NKG2A) protein with high affinity and exhibit therapeutically desirable functional properties, such as for the treatment of, for example, cancer. Immunoconjugates, bispecific molecules, and pharmaceutical compositions comprising the anti-NKG2A antibodies of the invention are also provided. Nucleic acid molecules encoding the antibodies, expression vectors, host cells, and methods of treatment of, for example, cancer using the antibodies are further provided. Combination therapy, in which an anti-NKG2A antibody in the present disclosure is co-administered with at least one additional agent such as another antibody (e.g., anti-PD-1, anti-PD-L1, and/or anti-CTLA-4 antibodies), is also provided.