Considerable research has been conducted on the advancement of mobile technologies to facilitate vocabulary learning and acquisition in a second language (L2). However, whether mobile platforms lead to a comprehensive mastery of both receptive and productive vocabulary knowledge has seldom been addressed in previous literature. This study investigated English vocabulary learning from engagement with mobile-based word cards and paper word cards in the context of the Chinese university classroom. A total of 85 undergraduate students were recruited to take part in the study. The students were divided into two groups, a mobile learning group and a paper-based learning group, and tested on two word knowledge components: receptive knowledge of the form-meaning connection and productive knowledge of collocations. Both the digital and non-digital word cards enhanced L2 vocabulary learning, and the results showed that the mobile application (app) promoted greater gains than physical word cards.