Kristoff and Olaf have somewhat of a good friendship and are friendly towards each other. At first, Kristoff calls him creepy and is confused by the fact that Olaf (being a living, breathing frozen substance) would dream about summer and being in heat itself. He wants to break the ice and tell the happy snowman that his dream might not be all what he thinks it's cracked up to be, but Anna stops him by smacking him in the arm and scolding him. Kristoff still believes somebody has to to tell Olaf the truth about his dream eventually, but doesn't try to proceed to do it himself. However, he seemed to hold no animosity or dislike towards the snowman. He also warned Olaf to be careful and not be seen when they rushed back to the kingdom, possibly out of concern for Olaf since people might be frightened and attempt to harm him.
Olaf also seemed to consider Kristoff a good friend, despite the fact that during their first meeting he called Kristoff "a funny looking donkey". For example, Olaf showed worry for Anna and Kristoff and told them to run while he tried unsuccessfully to distract and hold off Marshmallow, indicating Olaf cared for their safety and that Olaf considered Kristoff a good friend as he wanted to save him. He also told Anna that Kristoff loved Anna and his act of returning her to Hans to save her was an act of true love, showing that he understood Kristoff well enough to become aware of his affection for Anna. However, Olaf did think Kristoff was crazy for a moment when Kristoff brought everyone to his family of "rocks" and warned Anna to run before his family of rocks revealed themselves to the group.
Although they do not have much interaction throughout the film, it would seem that Kristoff sees Olaf as a good friend and vice versa, which is made stronger by their equal love for Anna.