diff --git a/test/common/ops/sell.js b/test/common/ops/sell.js
index 11c9676c03..9631fb9650 100644
--- a/test/common/ops/sell.js
+++ b/test/common/ops/sell.js
@@ -75,6 +75,16 @@ describe('shared.ops.sell', () => {
     }
   });
 
+  it('returns an error when the requested amount is negative', (done) => {
+    try {
+      sell(user, {params: { type, key }, query: {amount: -42} });
+    } catch (err) {
+      expect(err).to.be.an.instanceof(BadRequest);
+      expect(err.message).to.equal(i18n.t('positiveAmountRequired', {type}));
+      done();
+    }
+  });
+
   it('reduces item count from user', () => {
     sell(user, {params: { type, key } });
 
diff --git a/website/client/components/shops/market/sellModal.vue b/website/client/components/shops/market/sellModal.vue
index cfeaef7b48..b22bd3fb74 100644
--- a/website/client/components/shops/market/sellModal.vue
+++ b/website/client/components/shops/market/sellModal.vue
@@ -26,7 +26,7 @@
           b.how-many-to-sell {{ $t('howManyToSell') }}
 
         div
-          b-input.itemsToSell(type="number", v-model="selectedAmountToSell", :max="itemCount", min="1")
+          b-input.itemsToSell(type="number", v-model="selectedAmountToSell", :max="itemCount", min="1", @keyup.native="preventNegative($event)")
 
           span.svg-icon.inline.icon-32(aria-hidden="true", v-html="icons.gold")
           span.value {{ item.value }}
@@ -141,6 +141,13 @@
 
         this.selectedAmountToSell = 1;
       },
+      preventNegative ($event) {
+        let value = $event.target.value;
+
+        if (isNaN($event.target.valueAsNumber) || Number(value) < 0) {
+          this.selectedAmountToSell = 0;
+        }
+      },
       sellItems () {
         this.$store.dispatch('shops:sellItems', {
           type: this.itemType,
diff --git a/website/common/locales/en/npc.json b/website/common/locales/en/npc.json
index 4b49e2ab65..033513630b 100644
--- a/website/common/locales/en/npc.json
+++ b/website/common/locales/en/npc.json
@@ -92,6 +92,7 @@
   "invalidTypeEquip": "\"type\" must be one of 'equipped', 'pet', 'mount', 'costume'.",
   "mustPurchaseToSet": "Must purchase <%= val %> to set it on <%= key %>.",
   "typeRequired": "Type is required",
+  "positiveAmountRequired": "Positive amount is required",
   "keyRequired": "Key is required",
   "notAccteptedType": "Type must be in [eggs, hatchingPotions, premiumHatchingPotions, food, quests, gear]",
   "contentKeyNotFound": "Key not found for Content <%= type %>",
diff --git a/website/common/script/ops/sell.js b/website/common/script/ops/sell.js
index 226bb3f114..a36f2c5fb6 100644
--- a/website/common/script/ops/sell.js
+++ b/website/common/script/ops/sell.js
@@ -17,6 +17,10 @@ module.exports = function sell (user, req = {}) {
   let type = get(req.params, 'type');
   let amount = get(req.query, 'amount', 1);
 
+  if (amount < 0) {
+    throw new BadRequest(i18n.t('positiveAmountRequired', req.language));
+  }
+
   if (!type) {
     throw new BadRequest(i18n.t('typeRequired', req.language));
   }