Background: Long-term conditions (LTCs) in children require a high level of self-management. Written action plans (WAPs) have been advocated to guide decision-making and support self-management but there is uncertainty about how WAPs "work" and what aspects are important for successful implementation.

Objective: To review and synthesize existing qualitative evidence about the design and use of WAPs across childhood LTCs.

Method: We undertook a systematic search of the literature (Medline, EMBASE, CiNAHL, PsycInfo, Web of science) from inception to May 2015; critically appraised included studies; and synthesized the findings, drawing on normalisation process theory.

Results: 3473 titles were screened and 53 papers read in full. Nine studies (four key, two minor and three of poor quality) contributed to our analysis, predominantly work on asthma from the USA and in specialist settings. WAPs may help to alleviate user worry and boost confidence. Confidence to act was closely linked to feelings of responsibility and authority. The value and use of WAPs are determined by multiple factors, and varies between different user groups. Logistical challenges include sharing a WAP between different stakeholders and keeping it up to date. Colour coding and pictures may enhance the appeal and usability of WAPS.

Conclusion: WAPs are complex interventions but our understanding of their use and value in children with LTCs is limited. WAPs need to meet the needs of users who have different requirements/levels of understanding and confidence according to their different roles. Future research into WAPs needs to be both disease and context-specific.