Cut the ends of the zucchinis off. Cut in half lengthwise and then cut each half into spears.
In a small bowl, whisk together the olive oil, lemon juice, and garlic.
Place the zucchini spears in a large bowl or in a large Ziploc bag. Pour the olive oil mixture over the zucchini. Season with salt and black pepper, to taste. Toss until zucchini spears are well coated. Let sit while you preheat the grill or grill pan.
Preheat an outdoor grill or grill pan to medium high heat.
Remove the spears from the bowl or bag and place directly on the hot grill, cut side down. Cook for 3 to 4 minutes per side, until the zucchini is tender and there are nice grill marks.
Transfer to a platter and garnish with freshly grated Parmesan cheese and fresh basil. Serve immediately.