Example portable trailer stands for supporting parked trailers are disclosed herein. Some example portable trailer stands disclosed herein comprise two telescopic posts supporting a generally horizontal beam. Some examples include spring-loaded retractable wheels for selectively installing and removing the trailer stand from underneath a trailer left parked on a driveway. After being positioned under the trailer, the posts extend to lift the beam solidly up against the underside of the trailer. To accommodate conditions where the driveway is not parallel to the trailer's underside, some example posts can be lengthened independently and have angular play that allows the beam to tilt. In some examples, the horizontal axle of the trailer stand wheels is perpendicular to the beam so that the trailer stand can be readily installed from either the front or side of the trailer. Some examples have a kingpin-receiving groove in the beam or have some other kingpin-receiving feature.