In this study, people who suffer from insomnia will be randomized to one of three study conditions. The first group receives a multicomponent internet-based cognitive behavioral self-help intervention. The second group has access to an internet-based self-help sleep restriction intervention. The third group is a waiting control group. In both active conditions additional care or treatment is allowed. The aim of the study is to investigate the effectiveness of a multicomponent internet-based cognitive behavioral self-help intervention as well as a stand-alone internet-based self-help sleep restriction intervention for insomnia symptoms compared to a waiting list. Assessments take place at baseline, and 8-weeks and 6-months post-randomization. After 8 weeks, participants in the waiting control group get access to the internet-based cognitive behavioural self-help intervention and also fill out questionnaires at 6-months post-randomization.