In a saucepan, combine blackberries, sugar, and water. Bring to a boil over medium heat.

Reduce heat and let simmer for about 10 minutes, stirring occasionally until the blackberries break down.

Remove from heat and stir in lemon juice.

Strain the mixture through a fine mesh strainer to remove seeds and pulp, pressing to extract as much liquid as possible.

Let the syrup cool before transferring to a bottle or jar for storage.