Cut the avocados in half. Remove and discard the pits and skins, then place the avocado flesh in a mixing bowl.
Using a fork, mash the avocados until they reach the desired consistency.
Squeeze the juice from the lime halves over the mashed avocados. Add the diced tomatoes, chopped onion, jalapeno, and cilantro to the bowl. Season with salt and black pepper.
Stir all the ingredients together until thoroughly combined.
Serve the guacamole in a bowl with tortilla chips or as a side to your favorite dishes.