Preheat grill to medium heat (350-400ºF). Slice zucchini from top to bottom into quarter inch slices, about 3 to 4 slices, depending on size of zucchini. .
Brush with olive oil on both sides and sprinkle with salt, pepper, and oregano.
Grill for 5 minutes, flip, and grill for another 4 to 5 minutes or until desired tenderness is achieved. Best served immediately.
Use yellow summer squash instead of zucchini, or combine the two.
Don't want to heat up the grill? You can use a grill pan on the stove with good results.
Grilled zucchini is best eaten right away. Wrap leftovers in an airtight container and refrigerate for up to two days. Reheat gently in the microwave. The texture will be somewhat softer but the taste is still excellent.