The 6dF Galaxy Survey (6dFGS) aims to measure the redshifts of around 150 000 galaxies, and the peculiar velocities of a 15 000-member subsample, over almost the entire southern sky. When complete, it will be the largest redshift survey of the nearby Universe, reaching out to about z∼ 0.15 , and more than an order of magnitude larger than any peculiar velocity survey to date. The targets are all galaxies brighter than Ktot= 12.75 in the 2MASS Extended Source Catalog (XSC), supplemented by 2MASS and SuperCOSMOS galaxies that complete the sample to limits of (H, J, rF, bJ) = (13.05, 13.75, 15.6, 16.75) . Central to the survey is the Six-Degree Field (6dF) multifibre spectrograph, an instrument able to record 150 simultaneous spectra over the 5°.7 -field of the UK Schmidt Telescope. An adaptive tiling algorithm has been employed to ensure around 95 per cent fibring completeness over the 17 046 deg² of the southern sky with | b | > 10° . Spectra are obtained in two observations using separate V and R gratings, that together give R∼ 1000 over at least 4000–7500 Å and signal-to-noise ratio ∼10 per pixel. Redshift measurements are obtained semi-automatically, and are assigned a quality value based on visual inspection. The 6dFGS data base is available at http://www-wfau.roe.ac.uk/6dFGS/, with public data releases occurring after the completion of each third of the survey.