Andrews followed up on wins in Holland and Weymouth with a victory in always competitive Finn class, a fleet once dominated by four-time Olympic champion Sir Ben Ainslie.
The 27-year old Scot was one of three British winners in Germany with Luke Patience and Joe Glanfield winning the men's 470 and Sophie Weguelin and Eilidh McIntyre picking up the first win of their partnership in the women's 470.
Double Olympic silver medallist Nick Rogers and Elliot Willis picked up the first podium of their new partnership, with a second place behind Patience and Glanfield.
“It feels pretty good to win here in Kiel and to pick up my third gold medal in a row,” said Andrews.
“We have had good breeze all week with ten-20 knots. It’s been quite shifty which has meant the fleet has been up and down all week so it has been really good to keep consistent and to be in the top three all but one race.
"The key has definitely been my boat speed, I have been sailing really quick which is nice to see.”
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