Harry Allison Johnston II (December 2, 1931 – June 28, 2021) was an American lawyer, politician and diplomat from Florida.

He attended the Virginia Military Institute, and he became a lieutenant in the United States Army after graduating.

In 1986, he sought the Democratic nomination for Governor of Florida, but lost in a close primary race.

In 1999, President Bill Clinton appointed him to serve as the United States Special Envoy for Sudan, a position he held until 2000.

Johnston died on June 28, 2021, aged 89, more than a decade after being diagnosed with Alzheimer's disease.