Purpose: To evaluate the influence of laser-activated irrigation by Er:YAG and Er:YSGG (LAI) protocols and Nd:YAG laser irradiation on the bond strength of self-adhesively cemented fiber posts to root canal dentine. Materials and Methods: The study sample consisted of 84 human single-rooted permanent teeth instrumented with ProTaper Next technique. After obturation, post space preparations were created for fiber-reinforced composite posts. The prepared specimens were divided according to the laser treatment of the post space preparations: group 1: LAI (Er:YAG) + saline solution (pulse energy: 20 mJ, repetition rate: 15 Hz); group 2: LAI (Er:YAG) + QMiX solution (pulse energy: 20 mJ, repetition rate: 15 Hz); group 3: LAI (Er,Cr:YSGG) + saline solution (pulse energy: 62.5 mJ, 20 Hz); group 4: LAI (Er,Cr:YSGG) + QMiX (pulse energy: 62.5 mJ, 20 Hz); Nd:YAG laser (pulse energy: 100 mJ, 10 Hz). Fiber-reinforced posts were cemented with a self-adhesive cement. The bond strength was evaluated by the push-out bond strength test, and the mode of failure was determined under a stereomicroscope. Kruskal-Wallis test was used for the intergroup comparative analysis with 5% level of significance. Results: The highest bond strength was recorded in the Er:YAG + QMiX group (mean 3.401 MPa) (p < 0.05), followed by the Er,Cr:YSGG and the Er:YAG + saline solution (mean 1.111 MPa and 1.094 MPa, respectively), which did not differ significantly (p = 0.232). The irradiation with the Nd:YAG laser caused similar bond strength as the Er,Cr:YSGG + QMiX (p = 0.942). Conclusion: All laser protocols enhanced the bond strength of the self-adhesive cement in root canals compared to only saline irrigation. The bond strength of the self-adhesive cement depended on the laser parameters and irrigant used for the LAI.