**Aims**: Some studies reported an increase of suicides after the start of daylight-saving-time (DST), but the evidence is mixed and more research about the putative mechanisms of disrupted sleep and/or change of exposure to natural light is needed. **Methods**: In our pre-registered study, we analysed suicide rates in relation to DST using daily suicide data from 1981 - 2022 from Austria, Switzerland, and Sweden. We compared the two weeks before and after DST with Poisson regression models and we also used changepoint analyses. To explore the putative mechanism of disrupted sleep, we repeated the analysis for retired people (65+ years) who are likely less bound to DST and for younger people up to 64 years of age. To explore the effect of changed exposure to daylight, we repeated the analysis separately for regions in the northern region (Sweden) and the southern regions (Austria/Switzerland) because twilight and exposure to daylight varies by latitude. **Results**: There was no significant increase of suicides after start of DST (adjusted incidence rate ratio IRR = 0.98, 95% CI 0.91 – 1.06, p = 0.66) or at the end of DST (adjusted IRR = 0.99, 95% CI 0.91 – 1.07, p = 0.76). There were no statistically significant findings among younger or older subgroups and also not in Sweden and Austria/Switzerland. No changepoints were detected. **Conclusions**: There were no significant changes of suicide rates after start of DST in our study. There was no or inconclusive evidence to support putative mechanisms, that is, change of exposure to light and disruption of sleep. Our study is one of the largest so far and was adequately powered to replicate positive findings of existing studies. Selective reporting or small actual effects may explain the mixed findings. Replications with larger samples to detect smaller effects which are nonetheless important to inform the debate about harms and benefits of DST are recommended.