Background: Humor is an important quality, which is highly effective in human communications. Despite its advantages, if humor is not used correctly, it may have unethical outcomes, springing to the mind a vague picture of humor’s intrinsic morality. Therefore, the current study sought to explain the nature of humor and compare it with similar concepts in order to establish its limits as a behavioral quality. To this end, the paper conducted a narrative review of existing definitions and theories in the relevant papers and books as well as English and Persian dictionaries.
 Conclusion: The results showed that humor (a quality) and sense of humor (a combination of personal attributes) are positive ethical concepts that may produce negative outcomes in case of the following: (1) imbalance and (funny) content violation (exceeding the humor limits), (2) excessive use of humor (in terms of frequency and periodicity). As a result, humor is likely to have unethical outcomes, but sense of humor is always a positive behavioral quality. To demarcate humor morally, it is necessary to compare it with similar and related concepts; such a comparison requires the following: (1) intention and purposefulness (positive and well-meant), (2) minor violation. In line with this, this paper compared humor with several similar concepts including witticism, jokes, sarcasm, irony, mockery, derision, teasing, etc.