Background: Tanzania is one of the countries where excessive iodine intake has been reported, to intervene, the identification of possible causes is required. This study aimed to assess iodine status and determine the critical contributors to excessive iodine intakes in schoolchildren aged 8-14 years. Materials and Methods: A total of 288 school children were randomly selected in this school-based cross-sectional study in Kinondoni municipality, Tanzania. Household salt samples were analyzed using iodine rapid field test kit while that was collected from retailers/wholesalers by iodometric titration. Spot urine samples were collected and analyzed for iodine levels using a modified microplate method following the Sandell-Kolthoff reaction. A lifestyle questionnaire was administered to schoolchildren to assess their eating frequency of discretionary foods and salts. Results: The mean salt iodine content was 53.94 ± 13.02, and over 90% of household salt was iodized. Median urinary iodine concentration (UIC) was 401 µg/L indicating excessive iodine intake, and one-third of the children had UIC >500 µg/L. Nearly all school children consume discretionary choices as snacks or part of a meal. Potato chips and fried cassava were the top two discretionary choices consumed with discretionary salt use (67.3%). Potato chips (adjusted odds ratio [AOR=9.04, 95% CI: 3.61-22.63]), fried cassava (AOR=11.08, 95% CI: 3.45-35.54) and groundnuts consumption for 4-7 days/week (AOR = 0.30 95% CI: 0.09-1.0) were significantly associated with iodine intake. Conclusion and Recommendation: The evidence of excessive iodine intakes observed in previous studies and in this study should alert the policymakers to consider adjustment of the amount of iodine added to salt along with the obligation of reducing discretionary foods and salt intake.