Karl Sven Woytek Sas Konkovitch Matthew Kruszelnicki, AM born in Helsingborg, Sweden is a scientist, who is best known as an author and science commentator on Australian radio and television. He is usually referred to as Karl Kruszelnicki or Dr Karl.

He holds degrees in mathematics, biomedical engineering, medicine and surgery. He has also studied astrophysics, computer science, and philosophy. He has worked as a physicist, labourer, roadie for bands, car mechanic, film-maker, hospital scientific officer, biomedical engineer, TV weatherman, taxi driver, and medical doctor. He regrets not becoming a professional brewer, gynaecologist or melon farmer.

Kruszelnicki is the Julius Sumner Miller Fellow in the Science Foundation for Physics at the School of Physics, University of Sydney.