The present invention provides settable compositions that comprise water and cement kiln dust. The settable compositions optionally may comprise an additive that comprises at least one of the following group: fly ash; shale; slag cement; zeolite; metakaolin; and combinations thereof. The settable compositions optionally may be foamed with a gas. Methods of cementing also are provided that comprise: providing the settable composition; introducing the settable composition into a location to be cemented; and allowing the settable composition to set therein. The location to be cemented may be above ground or in a subterranean formation.