Purpose of Review: Clinical practice guidelines in mental healthcare are viewed as an essential asset if appropriately developed and implemented. The purpose of this article was to review the existing literature on how guidelines should be implemented to optimize their impact on provider performance and patient outcomes in specialist mental healthcare settings. Recent Findings: Findings from recent studies suggest a trend toward an improvement in process and patient outcomes following guideline implementation. However, studies are heterogeneous in terms of design, implementation strategies and outcome measures, making it very difficult to draw firm conclusions about which implementation strategy is effective in different healthcare contexts. Summary: Current knowledge about how guidelines should be implemented is still sparse and inconclusive in mental healthcare. Future studies should attempt to employ more rigorous designs, including random allocation of patients or clusters of patients, to shed further light on this compelling issue. Research on guideline implementation strategies should additionally take into account potential barriers to knowledge translation, which can heavily influence the implementability of treatment recommendations.