Place strawberries into a heavy saucepan, add water, and bring to a boil. Stir, reduce heat to low, and simmer until strawberries soften, about 15 minutes.

Strain juice into a separate saucepan, using a fine mesh strainer; discard strawberry pulp. Stir in sugar until dissolves. Bring strawberry juice back to a boil a second time.

Reduce heat to medium and simmer for 5 minutes. Skim any foam from the top of the syrup. Turn off heat and let cool to room temperature.

Pour syrup into a lidded container and refrigerate.