We present the results of H I 21 cm observations of 139 actively star-forming dwarf galaxies obtained with the 305 m radio telescope at Arecibo Observatory. Our sample consists of all objects cataloged in objective-prism surveys for UV-excess or emission-line galaxies published prior to the start of the survey that have luminosities below MB=-17.0 and that are located within the declination limits of the Arecibo telescope. Galaxies from the Markarian, Michigan, Case, Wasilewski, Haro, and Zwicky lists are included. The sample spans a wide range of both H I gas content and star formation levels. A total of 122 objects (88%) were detected; 82 galaxies have been observed for the first time in H I. The median velocity width for our sample is 88 km.s–1, and the median H I gas mass is 3.0x108M☉. In general, the sample galaxies are gas-rich, with an average MHI/LB=1.3 after correcting for the luminosity enhancement due to the starburst. The progenitors of many of the star-forming dwarfs have higher MHI/LB than typically seen in samples of nearby ``normal'' galaxies, emphasizing their distinct nature.