Background Trigger finger is a common hand condition that occurs when movement of a finger flexor tendon through the first annular (A1) pulley is impaired by degeneration, inflammation, and swelling. This causes pain and restricted movement of the affected finger. Non-surgical treatment options include activity modification, oral and topical non-steroidal anti-inflammatory drugs (NSAIDs), splinting, and local injections with anti-inflammatory drugs. Objectives To review the benefits and harms of non-steroidal anti-inflammatory drugs (NSAIDs) versus placebo, glucocorticoids, or different NSAIDs administered by the same route for trigger finger. Search methods We searched CENTRAL, MEDLINE, Embase, CINAHL, CNKI (China National Knowledge Infrastructure), ProQuest Dissertations and Theses, www.ClinicalTrials.gov, and the WHO trials portal until 30 September 2020. We applied no language or publication status restrictions. Selection criteria We searched for randomised controlled trials (RCTs) and quasi-randomised trials of adult participants with trigger finger that compared NSAIDs administered topically, orally, or by injection versus placebo, glucocorticoid, or different NSAIDs administered by the same route. Data collection and analysis Two or more review authors independently screened the reports, extracted data, and assessed risk of bias and GRADE certainty of evidence. The seven major outcomes were resolution of trigger finger symptoms, persistent moderate or severe symptoms, recurrence of symptoms, total active range of finger motion, residual pain, patient satisfaction, and adverse events. Treatment effects were reported as risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs). Main results Two RCTs conducted in an outpatient hospital setting were included (231 adult participants, mean age 58.6 years, 60% female, 95% to 100% moderate to severe disease). Both studies compared a single injection of a non-selective NSAID (12.5 mg diclofenac or 15.0 mg ketorolac) given at lower than normal doses with a single injection of a glucocorticoid (triamcinolone 20 mg or 5 mg), with maximum follow-up duration of 12 weeks or 24 weeks. In both studies, we detected risk of attrition and performance bias. One study also had risk of selection bias. The effects of treatment were sensitive to assumptions about missing outcomes. All seven outcomes were reported in one study, and five in the other. NSAID injection may offer little to no benefit over glucocorticoid injection, based on low- to very low-certainty evidence from two trials. Evidence was downgraded for bias and imprecision. There may be little to no difference between groups in resolution of symptoms at 12 to 24 weeks (34% with NSAIDs, 41% with glucocorticoids; absolute effect 7% lower, 95% confidence interval (CI) 16% lower to 5% higher; 2 studies, 231 participants; RR 0.83, 95% CI 0.62 to 1.11; low-certainty evidence). The rate of persistent moderate to severe symptoms may be higher at 12 to 24 weeks in the NSAIDs group (28%) compared to the glucocorticoid group (14%) (absolute effect 14% higher, 95% CI 2% to 33% higher; 2 studies, 231 participants; RR 2.03, 95% CI 1.19 to 3.46; low-certainty evidence). We are uncertain whether NSAIDs result in fewer recurrences at 12 to 24 weeks (1%) compared to glucocorticoid (21%) (absolute effect 20% lower, 95% CI 21% to 13% lower; 2 studies, 231 participants; RR 0.07, 95% CI 0.01 to 0.38; very low-certainty evidence). There may be little to no difference between groups in mean total active motion at 24 weeks (235 degrees with NSAIDs, 240 degrees with glucocorticoid) (absolute effect 5% lower, 95% CI 34.54% lower to 24.54% higher; 1 study, 99 participants; MD -5.00, 95% CI -34.54 to 24.54; low-certainty evidence). There may be little to no difference between groups in residual pain at 12 to 24 weeks (20% with NSAIDs, 24% with glucocorticoid) (absolute effect 4% lower, 95% CI 11% lower to 7% higher; 2 studies, 231 participants; RR 0.84, 95% CI 0.54 to 1.31; low-certainty evidence). There may be little to no difference between groups in participant-reported treatment success at 24 weeks (64% with NSAIDs, 68% with glucocorticoid) (absolute effect 4% lower, 95% CI 18% lower to 15% higher; 1 study, 121 participants; RR 0.95, 95% CI 0.74 to 1.23; low-certainty evidence). We are uncertain whether NSAID injection has an effect on adverse events at 12 to 24 weeks (1% with NSAIDs, 1% with glucocorticoid) (absolute effect 0% difference, 95% CI 2% lower to 3% higher; 2 studies, 231 participants; RR 2.00, 95% CI 0.19 to 21.42; very low-certainty evidence). Authors' conclusions For adults with trigger finger, by 24 weeks' follow-up, results from two trials show that compared to glucocorticoid injection, NSAID injection offered little to no benefit in the treatment of trigger finger. Specifically, there was no difference in resolution, symptoms, recurrence, total active motion, residual pain, participant-reported treatment success, or adverse events.