In the past decade, numerous studies have examined the effects of social media or language learning apps on student vocabulary learning. However, the comparison of the impact of social media and language learning apps was found only in a few studies, with little attention paid to applications widely used in China. Therefore, two social media apps (QQ and WeChat) and one language-learning app (Baicizhan) were selected to examine their effects on vocabulary learning. During an eight-week experiment, a total of 72 participants were assigned to three groups that used different apps as their vocabulary learning assistants, and each group received instructions via QQ, WeChat, and Baicizhan, respectively. The analytical results showed significant differences between the group on pretest and post-test scores, indicating measurable improvements in vocabulary learning in all three groups. The language-learning app, Baicizhan, was found to be the most effective of the three apps for vocabulary learning. Additionally, the questionnaire results indicated that Baicizhan was more effective than the two social media apps, QQ and WeChat, and preferred by the students for vocabulary learning.