Presents a study which aims to investigate SPALEX, a Spanish lexical decision database by focusing on native Spanish speakers at a global scale and with a vast amount of words, to provide a useful tool for researchers exploring the acquisition and processing of this language in native and foreign contexts. SPALEX contains data from a Spanish crowd-sourced lexical decision mega study. The authors collected the data through an online platform from May 12th, 2014 to December 19th, 2017. The majority of the data was acquired during the first month of the experiment, when an advertising campaign was done in order to attract the public’s attention. Participants also had the option of publishing their results via social networks, which led to attract more participants in a snow-ball sampling fashion. Additionally, the database contains information on participants that voluntarily provided information about their gender, age, country of origin, education level, handedness, native language, and best foreign language. In each experimental session, participants responded to 70 words and 30 non-words presented randomly and without repetition. Accuracy in SPALEX is expressed as 1 for correct answers and 0 for incorrect answers. Based on participants’ responses, the authors calculated percentage known, a measure of the percentage of participants that know a particular word. (PsycINFO Database Record (c) 2018 APA, all rights reserved)