Model Railroader (MR) is an American magazine about the hobby of model railroading. Founded in 1934 by Al C. Kalmbach, it is published monthly by Kalmbach Media of Waukesha, Wisconsin. Commonly found on newsstands and in libraries, it promotes itself as the oldest magazine of its type in the United States, although it is the long-standing competitor to Railroad Model Craftsman, which - originally named The Model Craftsman - predates MR by one year.

MR is considered to be a general-interest hobby magazine, appealing to a wide range of hobbyists, rather than specializing in a particular scale, or facet of the hobby (such as prototype operations or scratch building and kitbashing). Model Railroader covers a variety of scales and modeling techniques for engines, rolling stock, right-of-way, structures, and scenery. It reviews products including ready-to-run models as well as kits, tools and supplies. The magazine presents blueprints and photographs of prototype equipment, as well as photographs of models and layouts.

A longstanding philosophy of modeling is manifest in its editorial features of layout design and operation, in which the model is viewed as a three-dimensional and temporal compression of the real world, so that, for example, the motive power, freight, trackage and scenery of a real-world railroad are formed into a layout which captures the spirit of not only the equipment and region of the railroad but also its purpose and how it operates.

The magazine is published under ISSN 0026-7341. Individual issues use the UPC 074820085486.