diff --git a/src/Core/Models/StaticStore/Plan.cs b/src/Core/Models/StaticStore/Plan.cs
index d70b58d94..e928986ef 100644
--- a/src/Core/Models/StaticStore/Plan.cs
+++ b/src/Core/Models/StaticStore/Plan.cs
@@ -13,6 +13,7 @@ namespace Bit.Core.Models.StaticStore
         public PlanType Type { get; set; }
         public short BaseUsers { get; set; }
         public bool CanBuyAdditionalUsers { get; set; }
+        public short? MaxAdditionalUsers { get; set; }
         public bool CanMonthly { get; set; }
         public decimal BaseMonthlyPrice { get; set; }
         public decimal UserMonthlyPrice { get; set; }
diff --git a/src/Core/Services/Implementations/OrganizationService.cs b/src/Core/Services/Implementations/OrganizationService.cs
index ce4735807..db0eefc70 100644
--- a/src/Core/Services/Implementations/OrganizationService.cs
+++ b/src/Core/Services/Implementations/OrganizationService.cs
@@ -87,6 +87,12 @@ namespace Bit.Core.Services
             StripeCustomer customer = null;
             StripeSubscription subscription = null;
 
+            if(signup.AdditionalUsers > plan.MaxAdditionalUsers.GetValueOrDefault(0))
+            {
+                throw new BadRequestException($"Selected plan allows a maximum of " +
+                    $"{plan.MaxAdditionalUsers.GetValueOrDefault(0)} additional users.");
+            }
+
             if(plan.Type == Enums.PlanType.Free)
             {
                 var ownerExistingOrgCount =
diff --git a/src/Core/Utilities/StaticStore.cs b/src/Core/Utilities/StaticStore.cs
index ef48888f9..aab327a49 100644
--- a/src/Core/Utilities/StaticStore.cs
+++ b/src/Core/Utilities/StaticStore.cs
@@ -106,6 +106,7 @@ namespace Bit.Core.Utilities
                     BaseAnnualPrice = 12,
                     UserAnnualPrice = 12,
                     CanBuyAdditionalUsers = true,
+                    MaxAdditionalUsers = 5,
                     CanMonthly = false,
                     Name = "Personal",
                     StripeAnnualPlanId = "personal-annual",