"How Will I Know" received mainly positive reviews. The song became Houston's second number one single on the United States Billboard Hot 100. It spent two weeks atop the chart and also became Houston's first chart topper on the Canadian RPM Singles Chart. In other regions, the song was successful, reaching the top ten in in Sweden, Norway, and United Kingdom and the top twenty in the Netherlands, New Zealand, and Switzerland.
The song's music video features scenes of Houston dancing in a strikingly designed setting of video screens and colored partitions. The music video gave Houston exposure to the teens and MTV, a feat which the black artists had traditionally found tough to achieve. It also received nominations at the 1986 MTV Video Music Awards in the categories of Best Female Video and Best New Artist in a Video, winning the former category. The song has been performed on many of her tours including Greatest Love Tour (1986) and her recent Nothing but Love World Tour (2009–10). "How Will I Know" is also featured as a remix on Houston's compilation album, Whitney: The Greatest Hits (2000), whereas the original version is featured on The Ultimate Collection (2007).