Many abiotic and biotic stresses can reduce plant growth and development. Low temperature is one of the most harmful abiotic stresses, particularly for plants that are tropical or subtropical in origin. To elucidate the molecular mechanisms underlying the cold-stress response, components involved in the signal transduction of cold stress have been characterized. In this study, we characterized a basic helix–loop–helix (bHLH) transcription factor encoding gene, SlICE1, from tomato (Solanum lycopersicum), which shows similarity with Arabidopsis ICE1. The expression of SlICE1 was observed in younger leaves, flowers, and green and red fruits. To characterize the function of SlICE1, overexpressing tomato lines were produced. SlICE1-overexpressing tomatoes exhibited chilling tolerance, and SlICE1 enhanced the expression of cold-responsive genes, such as SlCBF1 and SlDRCi7, as well as accumulation of ascorbic acid. The SlICE1 protein was degraded after cold treatment. These results indicate that SlICE1 enhances cold tolerance in tomatoes.