In the vegetative phase, it is very difficult to tell it apart from Dandelion. Once it is flowering, it also looks quite similar to weeds such as Catsear and Hawkbit.

Unlike Dandelion, Catsear and Hawkbit, Hawksbeard is an annual weed. It easily survives mowing due to having flat rosettes at soil level.
It can be differentiated from Catsear and Hawkbit as these both have bristly hairy leaves, whereas Hawksbeard and Dandelion have reasonably hairless leaves. Hawksbeard has branched, leafy flower stems, unlike Dandelion, Catsear and Hawkbit.