aɪˈɑːsoʊz ɔːɹ aɪˈæsoʊz;  aɪˈɑːsoʊz ɔːɹ aɪˈæsoʊz, ˈɔːlsoʊ ɪn lˈætɪnˌaɪzd fˈɔːɹm ˈaɪæsəs ɔːɹ ˈaɪəʃəs, wʌzɐ ɡɹˈiːk sˈɪɾi ɪn ˈeɪntʃənt kˈɛɹiə loʊkˈeɪɾᵻd ɔnðə ɡˈʌlf ʌv aɪˈɑːsoʊz nˈaʊ kˈɔːld ðə ɡˈʌlf ʌv ɡˈuːluːk, ˈɑːpəzˌɪt ðə mˈɑːdɚn tˈaʊn ʌv ɡˈuːluːk, tˈɜːki.
Iasos or Iassos (;  Iasós or  Iassós), also in Latinized form Iasus or Iassus (), was a Greek city in ancient Caria located on the Gulf of Iasos (now called the Gulf of Güllük), opposite the modern town of Güllük, Turkey.