The invention relates to novel TNF family ligand trimer-containing antigen binding molecules comprising (a) at least one moiety capable of specific binding to a target cell antigen, (b) a polypeptide comprising three ectodomains of a TNF ligand family member or fragments thereof that are connected to each other by peptide linkers and (c) a Fc domain composed of a first and a second subunit capable of stable association, and to methods of producing these molecules and to methods of using the same.