Length of hospital stay (LHS) after primary total hip arthroplasty (THA) constitutes a critical outcome measure, as prolonged LHS implies increased resource expenditure. Investigations have highlighted factors that affect LHS after THA. These factors include advanced age, medical comorbidities, obesity, intraoperative time, anesthesia technique, surgical site infection, and incision length. We retrospectively analyzed the effect of day of the week of primary THA on LHS. We reviewed the surgery and patient factors of 273 consecutive patients who underwent THA at our institution, a tertiary-care teaching hospital. There was a 15% increase in LHS for patients who underwent THA on Thursday versus Monday when controlling for other covariates that can affect LHS. Other statistically significant variables associated with increased LHS included American Society of Anesthesiologists grade, transfusion requirements, and postoperative complications. The day of the week of THA may be an independent variable affecting LHS. Institutions with reduced weekend resources may want to perform THA earlier in the week to try to reduce LHS.