K45 may refer to:
*
K-45 (Kansas highway), now part of U.S. Route 56
*
Dialog K45, a Sri Lankan smartphone
* , a corvette of the Royal Navy
* , a corvette of the Indian Navy
*
Junkers K 45, a German transport aircraft
*
Potassium-45, an isotope of potassium
*
Symphony No. 7 (Mozart), by Wolfgang Amadeus Mozart
{{Letter-Number Combination Disambiguation