Fulfillment of basic psychological needs has been postulated to be essential for mental health across the human life span. So far, validated domain-general instruments using the same items to assess these constructs in different age groups are lacking. To close this gap, we introduce the General Need Satisfaction and Frustration scale, a multidimensional instrument to capture fulfillment of the basic psychological needs for autonomy, competence, and relatedness in children and adults. The factor structure and correlates of this new instrument are examined in two cross-sectional studies with children (N = 185, age range = 7-14) and adults (N = 380, age range = 18-77), and one ambulatory assessment study with children (N = 84, age range = 8-10). Confirmatory factor analyses suggest adequate fit of the postulated six-dimensional measurement model (three needs, each split into satisfaction and frustration). Need satisfaction was linked to higher well-being, and need frustration was linked to higher ill-being in both children and adults. Findings suggest that the instrument introduced in this work is suitable to capture between-person differences as well as day-to-day fluctuations in the fulfillment of the basic needs for autonomy, competence, and relatedness in children and adults. The measurement instrument therefore is a useful tool to capture core ingredients for mental health in samples across a broad range of the human life span. (PsycInfo Database Record (c) 2022 APA, all rights reserved).