**Overview** To validate and assess the reliability of an online behavioural laterality battery, 392 participants completed the a range of tasks twice. This was pre-registered on the OSF: https://osf.io/fktmh We report that high reliability was observed for a dichotic listening, chimeirc faces, and finger tapping task. We also report a rhyme decision visual half-field task for which the reliability was less satisfactory. Thus, we are actively developing the rhyme task. **Materials** The materials required to run each task can be found in the *Materials* folder. It includes the spreadsheets required to run the task via Gorilla.sc. **Data** All (anonymised) can be found under the the *Reliability_300subjects* folder. The following files are outputted from Gorilla.sc: - Demographics.csv - Miles.csv - Porta.csv - EHI.csv - LexTALE.csv - day1_combined.csv - day2_combined.csv These are all required to run our pre-processing script. The pre-processing script outputs: - for_figs.csv - allsum_out.csv - LIsz0.csv - LIsz1.csv - LIsz2.csv - LIs0.csv - LIs1.csv - LIs2.csv These are used in the formal analysis scripts. **Analysis scripts** Two markdown scripts are available under *Analysis Scripts*. The *battery_preprocessing_v6_DB_split2.Rmd* file pre-processing the data. The *online_laterality_reliability.Rmd* script is used to analyse the data and write the manuscript. **Tasks** Running version of the dichotic listening, chimeric faces, and finger tapping tasks can be found at: https://gorilla.sc/openmaterials/104636 **Funding** This study was supported by an Advanced Grant from the European Research Council (694189).