Marinated Cucumbers, Onions, and Tomatoes is a refreshing, no-cook side dish that’s perfect for summer meals, BBQ spreads, or quick make-ahead lunches. The crisp cucumbers, juicy cherry tomatoes, and thinly sliced onions soak up a zesty vinaigrette that’s tangy, herbaceous, and lightly spicy—making every bite a burst of flavor. This vibrant mix is not only colorful but also easy to prepare and customizable to your taste.

This marinated vegetable salad fits seamlessly into any Mediterranean, Southern, or picnic-style spread. Whether you’re looking to clear out your garden harvest or just want a lighter side option to contrast rich entrées, Marinated Cucumbers, Onions, and Tomatoes delivers on freshness and flavor every single time.

What Is the Marinated Cucumbers, Onions, and Tomatoes?

Marinated Cucumbers, Onions, and Tomatoes is a chilled salad-style dish that combines raw vegetables with a simple vinegar-based dressing. Over time, the veggies absorb the flavors of the marinade, transforming basic ingredients into something bold and satisfying. Traditionally, this dish includes sliced cucumbers, halved cherry or grape tomatoes, and slivers of white or red onion. The marinade typically features vinegar, olive oil, garlic, herbs like parsley or dill, and sometimes a touch of sugar or chili flakes.

This dish is known for its versatility and make-ahead convenience—ideal for meal prepping or serving at outdoor gatherings. The longer it sits, the more flavorful it becomes, making it one of those rare recipes that gets better with time.

Ingredients for Marinated Cucumbers, Onions, and Tomatoes

2 cups sliced English cucumbers (about 1 large)
1 cup cherry or grape tomatoes, halved (use a mix of red and yellow for color)
½ small white onion, thinly sliced
⅓ cup olive oil
¼ cup white wine vinegar (or apple cider vinegar)
1 teaspoon dried parsley
½ teaspoon dried oregano
½ teaspoon red pepper flakes (adjust to taste)
1 teaspoon sugar (optional, to balance acidity)
1 clove garlic, minced
Salt and black pepper to taste

How To Make the Marinated Cucumbers, Onions, and Tomatoes

Step 1: Prep the Vegetables

Wash and dry the cucumbers and tomatoes thoroughly. Slice the cucumbers into ¼-inch thick rounds, and cut the cherry tomatoes in half. Thinly slice the onion into slivers that are easy to bite into.

Step 2: Mix the Marinade

In a medium bowl or measuring cup, whisk together olive oil, vinegar, minced garlic, parsley, oregano, red pepper flakes, sugar (if using), and a generous pinch of salt and black pepper. Stir until well combined.

Step 3: Combine and Toss

In a large bowl or jar, add the sliced cucumbers, tomatoes, and onions. Pour the marinade over the vegetables and toss until everything is evenly coated.

Step 4: Marinate and Chill

Cover the bowl or seal the jar, and place it in the refrigerator. Let the mixture marinate for at least 2 hours—overnight is even better for deeper flavor infusion.

Step 5: Serve

Give everything a quick toss before serving. Taste and adjust salt or vinegar as needed. Serve chilled, straight from the fridge.

What to Serve with Marinated Cucumbers, Onions, and Tomatoes

This marinated salad is the kind of side dish that pairs with almost everything. Serve it alongside grilled chicken, steak, or fish for a crisp, acidic contrast. It’s also perfect next to Southern classics like fried chicken or cornbread. Add it to a mezze platter with hummus, olives, and pita for a Mediterranean feel, or simply pile it next to sandwiches or wraps to keep lunch light and vibrant.

It also works beautifully as a topping—try spooning it over crostini, grain bowls, or even tacos for a fresh bite.

Top Tips for Perfecting Marinated Cucumbers, Onions, and Tomatoes

Use seedless cucumbers: English or Persian cucumbers hold up better in the marinade and don’t water down the mix.
Slice everything evenly: Uniform sizes help with consistent marination and a better texture overall.
Let it rest: While a quick marinate will still be tasty, giving it 4–24 hours in the fridge really lets the flavors bloom.

Want More Summer Salad Ideas?

You might also like the Tomato Peach Burrata Salad, which balances sweet fruit with creamy cheese and basil. Or try Grilled Zucchini and Feta Salad for a smoky, tangy option straight off the grill.

For more refreshing veggie sides, check out my Chilled Green Bean Salad with Dijon Vinaigrette or the always-popular Watermelon Cucumber Feta Bowl. And if you want something hearty, the Roasted Corn and Black Bean Salad is a meal in itself.

Part 4 is ready! You now have a printable version of the Marinated Cucumbers, Onions, and Tomatoes recipe with a clean layout that’s perfect for kitchen use or sharing. Let me know if you’d like to turn this into a downloadable PDF or make any edits!