Preheat the grill to medium-high heat.
While the grill is heating, prepare the green onions by trimming off the root ends and any wilted or discolored tops.
Place the green onions in a large bowl and drizzle them with olive oil, tossing to coat evenly.
Season with salt and pepper, to taste.
Once the grill is hot, place the green onions directly on the grill grates.
Grill the green onions for 2-3 minutes per side, or until they develop charred grill marks and begin to soften. Be sure to keep an eye on them to prevent burning.
Transfer to a serving platter once the green onions are grilled to your desired level of tenderness and char.