Heat a 4.5-quart soup pot over medium heat. Add OLIVE OIL and heat until shimmering.
Add the ONION, CELERY, and CARROTS. Sauté for 5–7 minutes until softened. Stir in the GARLIC and cook for 30 seconds until fragrant.
Add the ITALIAN SEASONING and cook for another minute to bloom the flavors.
Pour in the CHICKEN BROTH and increase the heat to bring to a boil.
Add the CHICKEN BREASTS, reduce the heat, and simmer until they reach a minimum internal temperature of 160°F on an instant-read thermometer.
Use clean tongs to transfer the CHICKEN to a covered dish and let it rest for 5 minutes to reach 165°F through carryover cooking.
Stir in the ORZO PASTA and simmer for 8–10 minutes, stirring occasionally, until the orzo is tender.
Stir in the LEMON JUICE and LEMON ZEST.
Shred the CHICKEN with forks or your hands, then return it to the pot. Simmer for a few more minutes to heat through.
Season with SALT and PEPPER to taste.
Serve warm, garnished with FRESH PARSLEY and FRESH DILL.
Video
Notes
Chicken swap: Boneless chicken thighs can be used in place of chicken breasts. They typically cook about 5 minutes faster, so check for doneness a bit earlier.Pre-cooked chicken option: I like to use rotisserie chicken to save time when I don't want to use fresh chicken. For the best texture, add it near the end of cooking and warm it gently to prevent drying out.Extra lemon flavor: Use the zest and juice from 2 lemons for even more pronounced lemony brightness.Using dried herbs: If using dried parsley or dried dill, add them earlier in the simmering process so they have time to hydrate and flavor the broth.Add leafy greens: Stir in a few handfuls of fresh spinach, kale, or chopped Swiss chard during the last few minutes of simmering for extra color, nutrients, and texture.