Western psychology and social sciences have long emphasized the value of a positive attitude toward oneself. Previous research had developed psychometric tools assessing self-compassion, defined as being open to and moved by one’s own suffering. However, self-compassion did not describe whether people actually applied such protective factors when acutely faced with threats. The Unconditional Self-Kindness Scale (USKS) was developed as a tool to measure the behavioral response of self-kindness during an acute presence of threat to the self and not just as a general attitude when threat is absent. Since it can be experienced even in the most challenging situations and may promote resilience, this kindness may be defined as unconditional. We validated the Italian version of the USKS and found that the scale retained a one-factor structure. The USKS showed sound psychometric properties and good convergent validity since it was found to show very strong correlations with the Self-Compassion Scale-Short-Form and the Reassure Self subscale of the Forms of Self-criticizing/Attacking and Self-Reassuring Scale (FSCRS). In addition, the USKS showed good discriminant validity since it was found to show a negative moderate correlation and a negative strong correlation with the HS subscale and with the IS subscale of the FSCRS, respectively. Finally, the USKS showed good test–retest reliability and its use is encouraged in clinical and research settings in which the assessment of a positive attitude toward oneself during an acute presence of threat to the self is of interest.