Ecological momentary assessment (EMA) methodologies are commonly used to illuminate the predictors and impacts of experiencing subjective stress in the course of daily life. The validity of inferences from this research is contingent on the availability of measures of perceived momentary stress that can provide valid and reliable momentary stress scores. However, studies of the development and validation of such measures have been lacking. In this study, we use an EMA data collection design to examine the within- and between- person reliability and criterion validity and between-person gender measurement invariance of a brief EMA-adapted measure of a widely used trait measure of stress: the Perceived Stress Scale (PSS). Scores showed high internal consistency reliability and significant correlations with a range of criterion validity measures at both the within- and between-person level. Gender measurement invariance up to the scalar level also held for scores. Findings support the use of the EMA-adapted PSS presented in the current study for use in community-ascertained samples to address research questions relating to the influences on and effects of momentary stress and their gender differences.