Pre-heat oven to 425 degrees and line a baking sheet with foil. Toss trimmed asparagus in olive oil, salt and pepper and place on prepared baking sheet in a single layer. Roast until tender and caramelized, about 12-15 minutes.
While asparagus is roasting, prepared the tzatziki sauce; set aside until ready to serve.
Drizzle roasted asparagus with fresh lemon juice before serving with tzatziki sauce.