We examined event-related electroencephalography (EEG) oscillations, including event-related spectral perturbations (ERSP) and intertrial coherence (ITC), to compare feedback processing during a chance-based reward vs. non-reward task in groups of 10-12-year-old (n= 42), 13-14-year-old (n= 34) and 15-17-year-olds (n= 32). Because few, if any studies have applied these analytic methods to examine feedback processing in children or adolescents, we used a fine-grained approach that explored one half hertz by 16. ms increments during feedback (no win vs. win events) in the theta (4-8. Hz) frequency band. Complex wavelet frequency decomposition revealed that no win feedback was associated with enhanced theta power and phase coherence. We observed condition and age-based differences for both ERSP and ITC, with stronger effects for ITC. The transition from childhood to early adolescence (13-14. yrs.) was a point of increased differentiation of ITC favoring no win vs. wins feedback and also compared to children or older adolescents, a point of heightened ITC for no win feedback (quadratic effect). © 2013 Elsevier Inc.