Combine water and sugar in a medium saucepan over medium-high heat and bring to a boil.
Lower to a simmer and add strawberries to saucepan. Stir to combine.
Let simmer until sugar is dissolved and syrup begins to thicken, about 10 minutes.
Remove from heat and strain syrup through a fine mesh sieve into a heatproof container like a bowl or a mason jar. Press down on strawberries with a wooden spoon to extract as much liquid as possible. Discard strawberries or use them for something else (they make a delicious ice cream topping!)
Place bowl or jar in fridge to cool completely before using. Syrup will continue to thicken as it cools.