Gather all your ingredients and prep your vegetables by dicing carrots, celery, and onion. Shred your cooked chicken and have fresh herbs and lemon ready at hand.
Heat a large heavy-bottomed pot over medium heat and add olive oil. Once shimmering, add diced onions, carrots, and celery. Sauté until vegetables are tender and fragrant, about 5 minutes, with gentle stirring.
Pour in the chicken broth and bring to a gentle simmer. Add dried thyme and season with a pinch of salt and pepper. Let the broth simmer for about 10 minutes to develop flavors.
Add the shredded cooked chicken to the simmering broth, stirring to combine. Continue to simmer gently until the chicken is heated through, about 5 minutes.
Taste the broth and adjust seasoning with more salt and pepper if needed. Squeeze in the juice of half a lemon and add the lemon zest for brightness. Stir well and let simmer for another 2 minutes.
Remove the soup from heat and sprinkle with chopped fresh parsley. Ladle into bowls, ensuring each serving has a good mix of vegetables, chicken, and a bright, zesty broth.
Enjoy your vibrant, comforting lemon chicken soup—bright, flavorful, and perfect for a cozy weeknight dinner.