The observer effect (OE), the idea that observing a phenomenon changes it, has important implications across scientific disciplines involving measurement and observation. While often viewed as a confounding variable to control for, this paper argues that the OE should be seriously accounted for, explored, and systematically leveraged in research and clinical settings. Specifically, mindfulness practices that cultivate present-moment, nonjudgmental awareness are proposed as a platform to account for, explore, and intentionally harness the OE. In research contexts, mindfulness training may allow participants to provide more precise self-reports by minimizing reactive biases that perturb the observed phenomena. Empirical evidence suggests that mindfulness enhances interoceptive awareness and reduces automatic judgment, potentially increasing measurement sensitivity, specificity, and validity. Clinically, psychotherapies often aim to make unconscious patterns explicitly observable to the client, capitalizing on the transformative potential of observation. Mindfulness directly cultivates this capacity for meta-awareness, allowing individuals to decenter from rigid cognitive-emotional patterns fueling psychopathology. Rather than avoiding unpleasant experiences such as cravings or anxiety, mindfulness guides individuals to simply observe these phenomena, reducing identification and reactivity. Mindfulness practices may leverage components of the OE, facilitating lasting psychological change. To further study the OE, developing an OE index to code observer influence is proposed. Overall, this paper highlights the ubiquity of the OE and advocates developing methods to intentionally account for and apply observer influences across research and therapeutic contexts.