Niels \ni(e)-ls\ as a boy's name is of Danish origin. Variant of Neil (Irish, Gaelic) "champion".
For more information, see also the related name Nicholas.
Baby names that sound like Niels are Nels and Nils. Other similar baby names are Niel, Noel, Neely, Neel, Mills, Niles, Nile, Niall, Nial, Neils, Nilos, Nikos, Niklos, Niklas, Nicos, Sills and Wills.