Kostanjevica may refer to several places in Slovenia:
Kostanjevica na Krasu, a settlement in the Municipality of Miren-Kostanjevica Kostanjevica na Krki, capital of the Municipality of Kostanjevica na Krki Kostanjevica, Šentrupert, a settlement in the Municipality of Šentrupert Municipality of Kostanjevica na Krki Municipality of Miren-Kostanjevica