Fill a large pot with lightly salted water and bring to a rolling boil over high heat. Stir in spaghetti and return to a boil. Cook spaghetti uncovered, stirring occasionally, until tender yet firm to the bite, about 12 minutes. Drain well in a colander set in the sink.

Meanwhile, heat olive oil in a large skillet over medium heat. Stir in bacon; cook until bacon begins to shrink, about 3 minutes. Add garlic; continue cooking and stirring until garlic is softened and bacon is crisp, about 5 minutes.