Combine all the marinade ingredients together and pour it over the chicken thighs in a large ziplock bag. Marinade for 8-12 hours in the fridge.
To make the tzatziki sauce, combine all the ingredients in a bowl and store in the fridge until ready for use. Adjust the salt to taste if needed.
Remove the chicken from the bag and heat a grill over medium high heat.
Grill the chicken for 4-6 minutes per side, or until the internal temperature reaches 160°F.
Remove from the grill and let it rest for 5 minutes. Slice the chicken into strips or chunks.
Warm the pita breads in an oven or the microwave (optional) and serve the chicken rolled in the pita bread with the tzatziki sauce, lettuce, cucumber, tomato, red onion and feta cheese.
Notes
For optimal flavor, marinade the chicken for at least 8 hours, but not more than 12 as it will start to get mushy.
The typical easy gyro sauce is tzatziki sauce, but you can use any sauce you'd like! I included some options in the serving options section of the post.
The chicken is done cooking when the internal temperature reaches 160°F. Use a thermometer to check doneness easily.
Squeeze as much liquid out of the cucumber as you can before adding it to the yogurt sauce - it helps ensure the sauce stays thick and creamy.
You can substitute beef, pork or lamb for the chicken to make a beef gyro, lamb gyro or pork gyros.