Objective Two studies were conducted to assess the construct validity of the Symptom Interpretation Questionnaire (SIQ) with particular attention to its relationship to social desirability, daily symptom, mood, hassles reports, and personality. Methods Participants completed a battery of self-report measures collected at one point in time and completed several measures on a daily basis for 60 days. The three subscales of the SIQ (Psychological, Somatic, Normalizing) were correlated with theoretically related and unrelated constructs to assess its convergent and discriminant validity. Results The Psychological Attribution scale was associated with a negative reporting style as evidenced by its association with low social desirability, neuroticism, and the report of psychological and physical symptoms, negative mood, and hassles. Somatic Attributions were inconsistently associated with daily somatic symptom reports and doctor visits, but were not associated with negative mood or hassles. Normalizing Attributions were not associated with social desirability or doctor visits, but were inconsistently related to daily negative mood and hassles. Normalizing attributions were also inconsistently related to “healthy” aspects of personality. Conclusion These results suggest that the SIQ has a small degree of convergent validity but little discriminant validity, making it difficult to ascertain exactly what this measure taps.