You wouldn't think of Santiago as being a vegetarian's paradise, but you can do surprisingly well (especially if you are ovo-lacto, but even if not), if you choose some of these very veggie friendly (and in some cases, veggie) restaurants. You need to be careful to specify "no meat" on anything you eat, including dishes titled "vegetariano" which occasionally have a piece of rolled up sandwich meat atop them. It's not all pizza and cheese sandwiches, now get out there and explore.
Luis Pasteur 5393, vitacura
Top notch gourmet-ish vegetarian restaurant in pretty, upscale Vitacura...
Huérfanos 827, local 18
To eat healthy and well...
Avenida Vitacura 2751
Enjoy healthy eating...
Orrego Luco 54
(Providencia)
A rustic setting for vegetarians...
De La Olleria, 962
Hidden, lunchtime-only Thai restaurant with delicious curries...
Grajales 2085
Students and locals-only haunt with seriously good, gigantic and cheap sandwiches...
Seminario 400
Quality Pizzas, salads and appetizers in a cozy yet hip setting...
Avenida Irarrázaval, 2423
Unassuming tratoría with the best pizza in Santiago...
Las Urbinas 56
Tasty tex-mex and gringo treats in a comfy, airy bar with a nice rooftop patio with a great atmosphere...