In Spain in general it might be a bit complicated to be a vegetarian, not to mention a vegan. But in Barcelona it's not that difficult, more and more places keep popping up. Here are a few of my favorites:
Quinoa Bar - A tiny little vegetarian place, good food and lots to choose from.
Travessera de Gràcia 203
Enrique Granados 153
Väcka - A small place but packed with vegan goodies to have there or to take away. You can even order it online! They have a lot of gluten-free, sugar-free options, and even vegan ice cream. I love their gluten-free waffle with rawtella. More info here!
Travessera de Gracia 126
Flax & Kale – The trendiest healthy place in the city. Gorgeous space and good food that even a meatlover gets excited about.
Carrer dels Tallers 74
Teresa Carles – A long menu filled with tasty vegetarian food.
Carrer de Jovellanos 2
Teresa’s – The newest piece of the Teresa Carles empire, best for take-away. Great set of juices.
Calle Argenteria 31
Woki Market – Vegetarian food on the go, inside an organic shop.
Ronda de la Universitat 20 / Passatge Marimon 5 / Passeig Maritím de la Barceloneta / Calle Astúries 22
Calle del Hospital 78
Carrer d'Aragó 8
Carrer del Palau 5
Rebelot – Slow food: local produces, healthy and vegetarian. Very tasty!
Carrer del Baluard 58
Carrer de la Princesa 57
Sopa - I have lunch here several times a week, and the lunch menu is great value for money. It's vegetarian, vegan and macrobiotic. The space is nice too, and they have a terrace if you prefer to have your lunch in the sun.