The invention relates to HDAC inhibitors, or combinations comprising an HDAC inhibitor and a PI3K inhibitor for the treatment of non-hodgkin's lymphoma in a subject in need thereof. Also provided herein are methods for treating non-hodgkin's lymphoma in a subject in need thereof comprising administering to the subject a therapeutically effective amount of an HDAC inhibitor, or a combination comprising an HDAC inhibitor and a PI3K inhibitor.