ABSTRACT Purpose Fluoride varnish can decrease shear bond strength (SBS) of orthodontic brackets to enamel. Recently, laser has been used as a method of enamel preparation for bracket bonding. The present study aimed to compare SBS of orthodontic brackets on fluoridated and non-fluoridated teeth prepared by acid and laser etching. Materials and methods In this in-vitro study, 84 human extracted maxillary first premolars were divided into 4 groups: (1) fluoride varnish + acid-etching (AF); (2) fluoride varnish + laser-preparation (LF); (3) acid-etching (A); (4) laser-preparation (L). AF and LF groups were exposed to fluoride varnish and after 6 hours were washed. Samples in AF and A groups were prepared with 37% phosphoric acids and LF and L groups were etched by Er,Cr:YSGG laser. Afterwards, brackets were bonded. The samples were assessed by universal testing machine for SBS. Adhesive remnant index (ARI) was assessed under magnification in stereomicroscope. Statistical analysis was done by ANOVA analysis. P-value was considered to be 0.05. Results Maximum and minimum SBS were observed in A (SBS = 18.77) and AF (SBS = 2.78) groups, respectively. SBS of fluoridated laser-etched teeth (LF) was more than fluoridated acid-etched teeth (A). SBS was less than acceptable clinical bond strength in AF group. ARI was similar between groups (P-value < 0.097). Conclusion Fluoride varnish decreased SBS of brackets to enamel. Laser caused more SBS in fluoridated teeth than acid etched teeth. Thus, enamel preparation by laser may be considered a successful method in fluoridated teeth. Randomized controlled trials are recommended for this issue.