The literature into the effectiveness of mobile language learning applications on language outcomes remains scarce. In the current research, we sought to determine whether experimentally validated mobile applications for language acquisition exist and what learning principles could contribute to optimal learning with mobile applications. We conducted a meta-analysis on the current experimental literature assessing learning outcomes while using mobile-based language applications. We found a strong overall effect (g=1.03, k=27) of learning achievement using mobile language applications. An adjusted effect size of g=0.71 was discovered after publication bias correction, revealing significant publication bias in the field. We also found insufficient power in over half of included studies. Our results demonstrate that experimentally validated applications exist and provide evidence for mobile applications as a tool for second language learning. However, findings should be treated with caution as publication bias and low power present in the field could skew the effects. Future studies should replicate and extend the current observations with adequately powered experiments.