Some epidemiological evidence suggests that diets high in omega 3 fatty acids (n-3 FAs) may be beneficial for skeletal health. The aim of this systematic review was to determine if randomized controlled trials (RCTs) support a positive effect of n-3 FAs on osteoporosis. A systematic search was performed in PubMed and EMBASE databases. We included RCTs with skeletal outcomes conducted in adults or children (> = 1 year old) using n-3 FA fortified foods, diets or supplements alone or in combination with other vitamins/minerals, versus placebo. Primary outcomes were incident fracture at any site and bone mineral density (BMD) in g/cm2. Secondary outcomes included bone formation or resorption markers and bone turnover regulators. A total of 10 RCTs met inclusion criteria. Effect sizes with 95 % confidence intervals were estimated to compare studies across various treatments and outcome measures. No pooled analysis was completed due to heterogeneity of studies and small sample sizes. No RCTs included fracture as an outcome. Four studies reported significant favorable effects of n-3 FA on BMD or bone turnover markers. Of these, three delivered n-3 FA in combination with high calcium foods or supplements. Five studies reported no differences in outcomes between n-3 FA intervention and control groups; one study included insufficient data for effect size estimation. Strong conclusions regarding n-3 FAs and bone disease are limited due to the small number and modest sample sizes of RCTs, however, it appears that any potential benefit of n-3 FA on skeletal health may be enhanced by concurrent administration of calcium.