diff --git a/src/PersonalMilestone/personalmilestone.schema.ts b/src/PersonalMilestone/personalmilestone.schema.ts
index 423e340..90d1f11 100644
--- a/src/PersonalMilestone/personalmilestone.schema.ts
+++ b/src/PersonalMilestone/personalmilestone.schema.ts
@@ -174,6 +174,45 @@ export class PersonalMilestoneSchema extends PothosSchema {
           })
         },
       }),
+      deletePersonalMilestone: t.prismaField({
+        type: this.personalMilestone(),
+        args: {
+          personalMilestoneId: t.arg({
+            type: 'String',
+            description: 'The ID of the personal milestone to delete.',
+            required: true,
+          }),
+        },
+        description: 'Delete a personal milestone.',
+        resolve: async (_query, _root, args, ctx, _info) => {
+          if (ctx.isSubscription) {
+            throw new Error('Not allowed')
+          }
+          if (!ctx.http.me) {
+            throw new Error('Cannot get your info')
+          }
+          // check if the user is mentor of the schedule where the personal milestone belongs to
+          const personalMilestone = await this.prisma.personalMilestone.findUnique({
+            where: { id: args.personalMilestoneId },
+          })
+          const schedule = await this.prisma.schedule.findUnique({
+            where: { id: personalMilestone?.scheduleId },
+          })
+          if (schedule?.managedServiceId) {
+            const managedService = await this.prisma.managedService.findUnique({
+              where: { id: schedule.managedServiceId },
+            })
+            if (managedService?.mentorId !== ctx.http.me.id) {
+              throw new Error('Unauthorized')
+            }
+          }
+          return this.prisma.personalMilestone.delete({
+            where: {
+              id: args.personalMilestoneId,
+            },
+          })
+        },
+      }),
     }))
   }
 }