Global migration has contributed to greater language diversity in many parts of the world. Many migrants experience language barriers in their adopted countries. Language barriers hinder access to healthcare, including mental health. There exists little research on the extent of communication difficulties during language discordant mental health services. A cross-sectional observational study design was used to examine prevalence of communication challenges, use of communication best practices, and training needs among mental health providers and interpreters working with immigrants with Limited English Proficiency (LEP) in the United States. Using snowball sampling methods, 38 providers and 34 interpreters were recruited to complete online surveys. Challenges reported by interpreters pertained to technicalities of communication, while those reported by providers pertained to content of communication. Communication best practices such as pre-session briefings and post-session debriefings were used infrequently by providers in the sample. Providers with higher education levels were more likely to endorse some best practices. Fifty-four percent of the providers and 84% of the interpreters were interested in additional training in working with patients with LEP. Findings suggest the need for customized trainings for providers and interpreters to improve the quality of mental healthcare for patients with LEP.