This quick marinated tomato and onion salad is in constant rotation during the summer! It’s light, can be made ahead of time, and has just 4 main ingredients. Can’t beat that!
Grab your favorite seasonal tomatoes — we love these juicy campari tomatoes pictured below — then toss with thinly sliced sweet onion, extra virgin olive oil, and red wine vinegar. Season generously, then let the tomatoes and onion hang out in a fridge marinating for 1-2 hours. It’s just that simple, and you’ll be surprised how much flavor the quick marinade adds!
Favorite way to serve tomato and onion salad? Alongside savory breakfast or brunch recipes, as a healthier side dish for sandwiches (we love you chips, but we’ll see you next time!), or next to grilled meats. And because it’s gluten-free, dairy-free and vegan, it’s a great option when entertaining, regardless of food restrictions. You’ll make this all summer long, promise!

Ingredients For Quick Tomato And Onion Salad
- Tomatoes: this salad will be its absolute best during late spring and summer when tomatoes are at peak! We love cherry tomatoes, but grape, heirloom, Roma, or really any variety of tomatoes that are fresh will work.
- Sweet onion: for a bit of crunch and contrast of texture!
- Extra virgin olive oil
- Red wine vinegar
- Kosher salt + a pinch of flaky sea salt for serving!
- Black pepper
Why do we recommend smaller tomatoes, such as cherry or grape? They’ll hold up better during the marinade process. You can absolutely use something like a beefsteak tomato or heirloom tomatoes, but because their skin is much thinner — and you’ll end up cutting the tomatoes into chunks instead of halving or quartering them — you’ll end up with mushier tomatoes if they marinade for too long like this. Those larger varieties are best served right away.

Quick Salad Marinade
No need to whisk the olive oil and vinegar separately, simply season the tomatoes with Kosher salt and black pepper, then drizzle with the marinade ingredients and toss. Taste and adjust seasoning as needed, then refrigerate for 1-2 hours, or up to 24 hours.
If you’re adding any fresh herbs or cheese, add them before tossing with the marinade.

Variations On Tomato And Onion Salad
This is a pretty simple salad recipe. In fact, there are only 4 main ingredients (we don’t count Kosher salt and black pepper, those are absolute staples for every single recipe!). You can bulk it up by adding grilled chicken, steak, or salmon, but as far as veggies, we love to add the following: grilled or roasted zucchini or summer squash, fresh mozzarella or feta cheese, and lots of fresh herbs, whatever you’ve got on hand (basil, oregano, thyme, chives, cilantro — all great!).
Don’t have sweet onion? Red onion or thinly sliced shallots are perfect! Scallions are literally always in our fridge, so we add that a lot too.
If you happen to have ripe avocados needing to be used up and want something other than avocado toast, be sure to check out our avocado and tomato salad. Both of these salads are quick summer side dishes that go well with practically everything (breakfast, lunch, or dinner)!

What To Serve With Light Salads
We love serving lighter salads like this all year long, but especially in summer when the produce is at its peak. Here are some of our favorite entrées to pair this with, depending on the time of day:
- Breakfast: fried eggs, poached eggs, omelettes, hard boiled eggs, crab cake benedicts, breakfast polenta, fried potatoes and onions, green shakshuka with feta, cajun shrimp and grits
- Lunch: any and all sandwiches, such as a California club, deconstructed falafel sandwich, sourdough grilled cheese
- Dinner: filet mignon or other grilled meats, chicken Milanese, spatchcock chicken, lamb meatballs (or really any meatballs!)
Honestly, breakfast is our favorite time to enjoy this tomato salad! While we absolutely love toast and potatoes — common breakfast and brunch side dishes — sometimes we want something a little lighter to accompany eggs. This is a great gluten-free dish for when we are looking to go carb free.

Legit one of the easiest side dishes you can make. We enjoy some variation of this salad at least once a week during the summer months. Bet you’ll find it surprisingly addictive! If you make this Tomato and Onion Salad, please let us know by leaving a review and rating below!
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For more summer recipes we love, check out the following:
- Ahi Tuna Poké Bowls
- Mozzarella Caprese Gazpacho
- Watermelon Feta Salad
- Spatchcock Chicken
- Antipasto Salad
Tomato and Onion Salad Recipe
Ingredients
- 1 lb cherry tomatoes quartered
- ¼ sweet onion thinly sliced into half moons
- 2 Tbsp extra virgin olive oil
- 2 Tbsp red wine vinegar
- 1 tsp Kosher salt
- ¼ tsp freshly ground black pepper
- Flaky sea salt for serving
Instructions
- Add to a bowl. Place quartered tomatoes and thinly sliced onion in a large serving bowl, then season with 1 tsp Kosher salt and ¼ tsp black pepper.
- Pour the marinade on top. Drizzle 2 Tbsp extra virgin olive oil and 2 Tbsp red wine vinegar right on top.
- Toss the salad. Toss to thoroughly coat, then taste and adjust seasoning as needed. Either serve immediately (with a pinch of flaky sea salt, if using) or cover and refrigerate for 1-2 hours, or up to 24 hours. Can be served cold or at room temperature.
Notes
- If using larger tomatoes (such as heirloom, beefsteak, etc.), salad is best served immediately. Those tomatoes will need to be cut into chunks (versus halved or quartered) and will soften quicker than smaller tomatoes in the marinade.
Yum! I threw this together with a grilled cheese for a super quick lunch and it was awesome! My husband and kids love everything that makes up this salad, so I will be sure to make it for them another time. Definitely a keeper — thanks so much!
It’s seemingly simple, but definitely has something about it that makes it special! Thanks, Tamara! xo, Ari