Narcolepsy management usually requires lifelong pharmacotherapy. However, we know little about adherence to prescribed treatment in narcolepsy. We assessed adherence to wakefulness-promoting agents in narcolepsy patients. We retrospectively assessed adherence to wakefulness promoting medication in patients with narcolepsy using the Medicines Possession Ratio (MPR). Three levels of adherence were defined: poor (≤50%), intermediate (51-79%), and good (≥80%). Refractory daytime sleepiness was defined as an Epworth sleepiness scale (ESS) score >12 despite trialling at least three wakefulness-promoting agents. We compared demographic and clinical factors, and prescribed medications between patients, stratified by levels of adherence, as well as by presence or not of refractory sleepiness. We included 116 patients with narcolepsy (54.3% female, mean age 39.4 (±14) years). In sum, 93 (80.2%) patients had a diagnosis of narcolepsy type 1 (NT1), and 23 (19.8%) of type 2 (NT2). Suboptimal symptom control was common: 39.8% had refractory sleepiness, and 47.3% of NT1 patients had persistent cataplexy. Good adherence was seen in only 55.2% of patients, while 12.9% were intermediately and 31.9% poorly adherent. Patients with poor adherence were more likely to have a diagnosis of NT2, but adherence did not vary according to gender, age, the presence of psychiatric co-morbidity, or the presence of apparent intractable symptoms. Levels of good adherence to therapy were no better in patients with refractory sleepiness than in those with satisfactory symptom control (56.5% vs 54.3%; p = 0.81). Suboptimal adherence to prescribed therapy is common in narcolepsy patients, including those with apparent intractable symptoms, and particularly in patients with NT2.