"The Hardest Thing" is the third single released from American boy band 98 Degrees's second studio album, 98 Degrees and Rising (1998). "The Hardest Thing" peaked at number five in the United States, number 10 in Canada, number 29 in the United Kingdom, and number 31 in Ireland. It also experienced moderate success in Oceania, peaking at number 24 in Australia and number five in New Zealand. The single was certified Gold by the Recording Industry Association of America (RIAA) for sales of 500,000 units.