Psychiatric medications such as antidepressants, antipsychotics, and anticonvulsants are commonly prescribed by physicians for the off-label use of improving sleep. Reasons for preferential prescription of these medications over FDA-approved insomnia drugs may include a desire to treat concurrent sleep problems and psychiatric illness with a single medication, and/or an attempt to avoid hypnotic drugs due to their publicized side effects. However, there have been few large studies demonstrating the efficacy and safety of most off-label medications prescribed to treat insomnia. In addition, many of these medications have significant known side effect profiles themselves. Here we review the pertinent research studies published in recent years on antidepressant, antipsychotic, and anticonvulsant medications frequently prescribed for sleep difficulties. Although there have been few large-scale studies for most of these medications, some may be appropriate in the treatment of sleep issues in specific well-defined populations.