Sitting typically falls into two distinct categories for babies; sitting supported initially, followed by sitting unsupported. We would expect to see babies able to sit with support from around 5-6 months, but of course it could be earlier or later than this depending on your baby’s unique development path. Unsupported (but still supervised) sitting is typically achieved around 7-9 months.
Adults usually help babies to sit up by supporting them on their lap, with cushions or products such as Mothercare Safari Sit Me Up Cosy. This makes sure that babies are helped to retain their sitting position before they are fully able to balance and support themselves. Remember that their head is the heaviest part of their body at this point and so they will tip over easily. Over time your baby will begin to open and stretch out their legs as a counter-balance to their heavy head and this will enable them to lean forward and reach things in front of them and in time they will be able to sit completely unsupported.