Cognomen Topolnjak (Topolnjak 
) , around the globe, is a rare last name. The surname Topolnjak is habitual in Croatia, where it is quite a rare surname, Germany, where it is a very rare surname, and Canada, where it is an extremely rare surname. Measured by absolute frequency, it most frequently occurs in Croatia, Germany, and China.
Mr, Neven, Emina, Vesna, Filip, Irena, Ivana, Ivona, Ivica, Zoran, Marica, Marija, Matija, Melita, Mirela, Mislav, Mladen, Suzana, Slavko, Krista, Renata, Dijana, Tanja, Josip, Jasna, Goran, Ana, Edo, Ema, Ida, Mile, Mijo, Asja, Luka, Vito, Ivan, Josipa, Mario, Saša, Aleks, Antun, Boris, Borna, Karlo, Rajko, Dario, Darko, Damir, Marko, and Jelena