We are a family that eats at Olive Garden every once in a while, especially when we are on the road. They are found around the country, so at times it makes for a good meal to stop off and grab dinner. While I was familiar already with some of the options we could order as a vegetarian family, I found recently that Olive Garden has put out a convenient list of what is vegetarian and vegan at their restaurants.
As you can see from their list, what they claim as the vegetarian options include alfredo sauce, breadsticks with butter, five cheese marinara sauce, white wine sauce, cheese ravioli with marinara, eggplant parmigiana, fettuccine alfredo, mushroom ravioli, etc. However... If you read what they wrote at the top of the page, it appears as though they include animal-based rennet as being vegetarian. That seems a little odd to me, as animal-rennet is not usually vegetarian, so you may want to stick to ordering from the list of vegan options. If it includes animal-based rennet then in my book it probably isn't vegetarian at all. I'd stick to ordering vegan, so that you know you are getting a vegetarian dish.
If you get their marinara sauce it is vegan, as are their pasta such as angel hair, spaghetti, small shells, etc. You can also ask them to make you a batch of breadsticks without the butter/plain and they will be vegan. The good news is that you can go to Olive Garden and eat vegan, by ordering some pasta with marinara sauce, plain breadsticks, and their minestrone soup. Their soup is good, so even just getting the soup and plain breadsticks would make for a good meal.
As someone who likes to dine out, I appreciate that Olive Garden has provided this information to vegetarians and vegans, so we can make informed food choices.
Take a look at the list below to see what options you have for ordering vegan and vegetarian at Olive Garden (click on an image to enlarge it):