Objectives: Sleep dysfunction and headaches are common and disabling conditions which are frequently comorbid with psychiatric disorders. Furthermore, there is a growing body of literature linking sleep dysfunction to the frequency and intensity of headaches. This study retrospectively examined the prevalence of insomnia and headache frequency, and their effects on general psychological treatment outcomes in a sample of patients attending a university psychology outpatient clinic in metropolitan Queensland, Australia. Methods: Outcome Questionnaire 45 data were extracted for 69 adult patients who presented to the Griffith University Psychology Clinic (Mount Gravatt, QLD) in 2018, and who consented to the use of their deidentified data for research purposes. Results: The prevalence of frequent insomnia and headaches in the week of patients' initial session were 47.8 and 23.2%, respectively. Additionally, there was a correlation, rs =.26, p =.02 between frequency of insomnia and headaches at the initial session. Frequent insomnia (odds ratio [OR] = 4.62, p <.01), headaches (OR = 3.82, p =.055, pbootstrapped =.04), and comorbid insomnia and headaches (OR = 7.25, p =.02) were strong predictors of inadequate treatment response, adjusting for age, sex, and number of therapy sessions. Effect sizes achieved by students were large (d = 0.9), and similar to those found in studies of fully qualified therapists. Conclusions: Our study demonstrates clinicians should be aware that sleep and headache problems may complicate psychological treatment of other problems, and that presence of these factors should warrant specific targeted attention early in treatment.