Wash the fruit. Hull strawberries to remove stems, then quarter them. (See Notes section below for tips on using frozen strawberries.)
In a medium saucepan, bring water and strawberries to a boil. Lower the heat and bring to a simmer for 15 minutes. Remove from heat.
Pour through a fine mesh strainer to strain the hot liquid into a bowl or jar. Discard solids.
While still warm, add sugar to the strawberry mixture and stir until sugar dissolves.
Let cool to room temperature. Store in an airtight container for up to two weeks.
Notes
If using frozen strawberries: You can use frozen berries for this syrup, ideally already sliced ones. Use them like you would fresh ones. If they are frozen whole berries, let them thaw first, then mash or slice them to use in this recipe. (Add any juices that melt, too!)