Background This study aimed to evaluate the efficacy of viscosupplementation after arthroscopic partial meniscectomy. Method A randomized controlled trial of 47 patients who underwent arthroscopic partial meniscectomy was conducted between March 2020 and March 2021. Patients were randomized into two groups: a viscosupplementation group (n = 23) and a control group (n = 24). A single-dose intraarticular hyaluronic acid injection was used as viscosupplementation. The 100 mm visual analogue scale (VAS) for pain assessment was measured at baseline and at 1 day, 2 weeks, 6 weeks, and 3 months post-surgery. The International Knee Documentation Committee (IKDC), Tegner, Lysholm, and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scores and range of motion (ROM) of the knee were measured at baseline, 2 weeks, 6 weeks, and 3 months. Results The 100 mm VAS score for pain was significantly lower in the viscosupplementation group at 2 weeks post-surgery (27.5 mm vs. 40.7 mm, P = 0.047). ROM was significantly greater in the viscosupplementation group than in the control group at 2 weeks (131.5° vs. 121.0°, P = 0.044) post-surgery. No significant differences were observed in the IKDC or in the Tegner, Lysholm, and WOMAC scores between the two groups. Conclusions Viscosupplementation after arthroscopic partial meniscectomy significantly reduced pain at 2 weeks post-surgery and improved ROM of the knee at 2 weeks post-surgery. There might be some benefits in terms of pain and functional recovery of viscosupplementation after arthroscopic surgery. Study design Randomized controlled trial; Level of evidence, 1. Trial registration This randomized controlled trial was registered at cris.nih.go.kr #KCT0004921.