This systematic review assessed low-level laser therapy (LLLT) for lateral elbow tendinopathy (LET) and examined the validity of treatment procedures and doses. Eighteen RCTs were identified with 13 RCTs (730 patients) meeting the criteria for meta-analysis. Twelve RCTs satisfied half or more of the methodological criteria. Publication bias was detected by Egger’s graphical test, which showed a negative direction of bias. Ten of the trials included patients with poor prognosis caused by failed steroid injections or other treatment failures, or long symptom duration or severe baseline pain. The weighted mean difference (WMD) for pain relief was 10.2 mm and the RR for global improvement was 1.36. Trials that targeted acupuncture points reported negative results, as did trials with wavelengths of 820, 830 and 1064 nm. In a subgroup of five trials with 904 nm lasers and one trial with 632 nm wavelength where the lateral elbow tendon insertions were directly irradiated, WMD for pain relief was 17.2 mm and 14.0 mm, respectively, while RR for global pain improvement was only reported for 904 nm at 1.53. LLLT doses in this subgroup ranged between 0.5 and 7.2 J. Secondary outcome measures of pain-free grip strength, pain pressure threshold, sick leave and follow-up data from 3 to 8 weeks after the end of treatment, showed consistently significant results in favour of the same LLLT subgroup. No serious side-effects were reported.