Provided are antibodies that specifically bind human astrovirus (HAstV) capsid spike protein. Fusion proteins and conjugates comprising such antibodies are also provided. Also provided are nucleic acids that encode one or both of the variable chain polypeptides of an antibody of the present disclosure, as are cells that include such nucleic acids. Also provided are compositions that include the antibodies of the present disclosure, including in some instances, pharmaceutical compositions. Methods of making and using the antibodies of the present disclosure are also provided. In certain aspects, provided are methods that include administering to an individual having or suspected of having a HAstV infection a therapeutically effective amount of an antibody, fusion protein or conjugate of the present disclosure.