The existing learners’ dictionaries for L2 learners of Spanish suffer from various shortcomings. They do not take full advantage of the new technologies, lack lexicographical data adapted specifically to the target users’ mother tongue and native culture, provide only partial assistance to text reception and offer unsatisfactory solutions to text production. Based on the lexicographical function theory, this paper will outline a model of an online dictionary for adult L2 learners of Spanish. To that end, we will present a concept that includes the most important functions and the main content which a dictionary for learners of a foreign language should have in order to meet the lexicographical needs of its users. As a matter of example, the paper also gives some suggestions on how to treat syntactic properties in a dictionary with these characteristics.