To make the simple syrup, combine sugar and 1/2 cup water in a medium saucepan over medium heat, stirring until sugar is dissolved, about 2-3 minutes; let cool.
Add strawberries to the bowl of a food processor and process until smooth, about 1-2 minutes; strain through a cheesecloth or fine sieve.
In a large pitcher, whisk together strawberry puree, lemon juice and simple syrup. Place in the refrigerator until chilled.