Both wild and pet rabbits can eat lettuce according to the House Rabbit Society. Pet owners should feed rabbits a balanced diet of purchased food pellets, hay, fruits and vegetables.
Greens of all kinds are an important part of any rabbit's diet. As vegetarians, they derive their nutrients from both leafy and hard vegetables and fruits. Choose fresh produce of different colors, with an emphasis on dark greens, as they contain the most vitamins. Romaine, bibb and leaf lettuce are all good choices. All vegetables are acceptable once the bunny is 12 weeks old.
Pellets are also an important part of a rabbit's daily diet. Purchase just enough pellets from a feed store to last for a week or two. Rabbits do not enjoy stale pellets any more than humans enjoy stale food.