Blend the garlic, olive oil, lemon juice, Dijon mustard, honey, oregano, thyme, salt, and pepper until smooth.
Place the chicken thighs in a sealable bag or container. Pour in the marinade, coat well, and refrigerate for at least 2 hours.
Preheat the oven to 425°F (220°C). Position the oven rack in the center.
Arrange the potatoes in a large baking dish. Pour half of the used marinade over the potatoes and toss until evenly coated.
Place the marinated chicken thighs skin-side up on top of the potatoes.
Drizzle the remaining marinade over the chicken.
Bake for 10 minutes at 425°F.
Reduce the oven temperature to 375°F (190°C) and continue baking for 45–55 minutes, or until the Greek Lemon Chicken and Potatoes reaches an internal chicken temperature of at least 185°F (85°C).
If the potatoes need additional cooking, transfer the chicken to a plate and loosely cover with foil. Increase the oven temperature back to 425°F and roast the potatoes until tender and golden.
Rest the chicken for 10–15 minutes before serving.
Garnish with fresh oregano and lemon wedges if desired.