The former swimmer, who competed in four Paralympic Games in the pool before switching to cycling in 2005, had already become Britain's most decorated Paralympian when she won the 3km pursuit on Monday September 12.
Storey completed the 20km course in a winning time of 27-22.42, which gave her the win by 1-30 to Poland's Anna Harkowska. Samantha Bosco (USA) took the third step on the podium.
The win took Paralympics GB to 35 golds, which is already better than the medal haul at London 2012.
Meet our Paralympians
"I wasn't 100% sure I had won it," Dame Sarah told official broadcaster Channel 4. "Your time checks are brilliant but until the announcer says it you're not sure.
"You focus on one race at a time and for me it was about getting a second gold at these Games and I got reminded I had 11 before these Games."
At 38-years-old, the champion cyclists show no signs of slowing down so an eighth consecutive Games isn't out of the question.
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