diff --git a/packages/destination-actions/src/destinations/hubspot/upsertObject/__tests__/validate.test.ts b/packages/destination-actions/src/destinations/hubspot/upsertObject/__tests__/validate.test.ts
index 442682540d..ca6d46c520 100644
--- a/packages/destination-actions/src/destinations/hubspot/upsertObject/__tests__/validate.test.ts
+++ b/packages/destination-actions/src/destinations/hubspot/upsertObject/__tests__/validate.test.ts
@@ -1,4 +1,9 @@
-import { mergeAndDeduplicateById, validate, ensureValidTimestamps } from '../functions/validation-functions'
+import {
+  mergeAndDeduplicateById,
+  validate,
+  ensureValidTimestamps,
+  deDuplicateAssociations
+} from '../functions/validation-functions'
 import { Payload } from '../generated-types'
 
 const payload: Payload = {
@@ -228,3 +233,77 @@ describe('ensureValidTimestamps', () => {
     expect(ts).not.toBeNaN()
   })
 })
+
+describe('deDuplicateAssociations', () => {
+  const createAssociationPayload = (id: string) => ({
+    object_details: {
+      object_type: 'contact',
+      id_field_name: 'email',
+      id_field_value: id,
+      from_record_id: 'from-123'
+    },
+    association_details: {
+      association_label: 'HUBSPOT_DEFINED:primary'
+    }
+  })
+
+  it('returns empty array when association groups is empty', () => {
+    expect(deDuplicateAssociations([])).toEqual([])
+  })
+
+  it('returns the same array when associations are unique within groups', () => {
+    const associationGroup1 = [createAssociationPayload('a@example.com'), createAssociationPayload('b@example.com')]
+    const associationGroup2 = [createAssociationPayload('c@example.com'), createAssociationPayload('d@example.com')]
+
+    const result = deDuplicateAssociations([associationGroup1, associationGroup2])
+    expect(result).toHaveLength(2)
+    expect(result[0]).toHaveLength(2)
+    expect(result[1]).toHaveLength(2)
+  })
+
+  it('removes duplicate associations within each group', () => {
+    const assocPayload = createAssociationPayload('a@example.com')
+    const duplicateGroup = [assocPayload, { ...assocPayload }, { ...assocPayload }]
+
+    const result = deDuplicateAssociations([duplicateGroup])
+    expect(result).toHaveLength(1)
+    expect(result[0]).toHaveLength(1)
+    expect(result[0][0]).toEqual(assocPayload)
+  })
+
+  it('keeps the last occurrence of a duplicate association within a group', () => {
+    const assoc1 = createAssociationPayload('a@example.com')
+    const assoc2 = {
+      ...createAssociationPayload('a@example.com'),
+      object_details: {
+        ...createAssociationPayload('a@example.com').object_details,
+        extra: 'last'
+      }
+    }
+
+    const associationGroup = [assoc1, assoc2]
+
+    const result = deDuplicateAssociations([associationGroup])
+    expect(result).toHaveLength(1)
+    expect(result[0]).toHaveLength(1)
+    expect(result[0][0]).toEqual(assoc2)
+  })
+
+  it('handles multiple groups with different duplicates', () => {
+    const group1 = [
+      createAssociationPayload('a@example.com'),
+      createAssociationPayload('a@example.com') // duplicate
+    ]
+
+    const group2 = [
+      createAssociationPayload('b@example.com'),
+      createAssociationPayload('c@example.com'),
+      createAssociationPayload('c@example.com') // duplicate
+    ]
+
+    const result = deDuplicateAssociations([group1, group2])
+    expect(result).toHaveLength(2)
+    expect(result[0]).toHaveLength(1) // deduped to 1
+    expect(result[1]).toHaveLength(2) // deduped to 2
+  })
+})
diff --git a/packages/destination-actions/src/destinations/hubspot/upsertObject/functions/validation-functions.ts b/packages/destination-actions/src/destinations/hubspot/upsertObject/functions/validation-functions.ts
index f9c1906cd1..cac349505b 100644
--- a/packages/destination-actions/src/destinations/hubspot/upsertObject/functions/validation-functions.ts
+++ b/packages/destination-actions/src/destinations/hubspot/upsertObject/functions/validation-functions.ts
@@ -1,6 +1,6 @@
 import { PayloadValidationError, StatsContext } from '@segment/actions-core'
 import { Payload } from '../generated-types'
-import { Association } from '../types'
+import { Association, AssociationPayload } from '../types'
 import { getListPayloadType, getListName } from '../functions/hubspot-list-functions'
 
 export function validate(payloads: Payload[], flag?: boolean): Payload[] {
@@ -21,23 +21,21 @@ export function validate(payloads: Payload[], flag?: boolean): Payload[] {
     )
   }
 
-  if (flag === true){
-    const hasEngageAudience = cleaned.some((p) => getListPayloadType(p) === 'is_engage_audience_payload') 
-    const hasNonEngageAudience = cleaned.some((p) => getListPayloadType(p) === 'is_non_engage_audience_payload') 
-    
-    if (hasEngageAudience && hasNonEngageAudience){
-      throw new PayloadValidationError(
-        'Engage and non Engage payloads cannot be mixed in the same batch.'
-      )
+  if (flag === true) {
+    const hasEngageAudience = cleaned.some((p) => getListPayloadType(p) === 'is_engage_audience_payload')
+    const hasNonEngageAudience = cleaned.some((p) => getListPayloadType(p) === 'is_non_engage_audience_payload')
+
+    if (hasEngageAudience && hasNonEngageAudience) {
+      throw new PayloadValidationError('Engage and non Engage payloads cannot be mixed in the same batch.')
     }
 
-    const listNames = Array.from(
-      new Set(cleaned.map((p) => getListName(p)).filter(Boolean))
-    )
+    const listNames = Array.from(new Set(cleaned.map((p) => getListName(p)).filter(Boolean)))
 
-    if (listNames.length > 1){
+    if (listNames.length > 1) {
       throw new PayloadValidationError(
-        `When updating List membership, all payloads must reference the same list. Found multiple lists in the batch: ${listNames.slice(0, 3).join(', ')}`
+        `When updating List membership, all payloads must reference the same list. Found multiple lists in the batch: ${listNames
+          .slice(0, 3)
+          .join(', ')}`
       )
     }
   }
@@ -66,7 +64,7 @@ export function validate(payloads: Payload[], flag?: boolean): Payload[] {
       return fieldsToCheck.every((field) => field !== null && field !== '')
     })
   })
-  
+
   return cleaned
 }
 
@@ -235,3 +233,32 @@ function isValidTimestamp(ts: unknown): ts is string | number | Date {
   }
   return false
 }
+
+/**
+ * Removes duplicate associations from the provided array based on a composite key
+ *
+ * @param associationGroups - An array of arrays of `AssociationPayload` objects.
+ * @returns An array of arrays of unique `AssociationPayload` objects.
+ */
+export function deDuplicateAssociations(associationGroups: AssociationPayload[][]): AssociationPayload[][] {
+  if (!associationGroups || associationGroups.length === 0) {
+    return associationGroups
+  }
+
+  return associationGroups.map((group) => {
+    if (!group || group.length === 0) return group
+
+    const associationKey = (assoc: AssociationPayload) =>
+      `${assoc.object_details.object_type}|${assoc.association_details.association_label}|${assoc.object_details.id_field_name}|${assoc.object_details.id_field_value}`
+
+    const uniqueAssociationsMap = new Map<string, AssociationPayload>()
+
+    for (const assoc of group) {
+      uniqueAssociationsMap.set(associationKey(assoc), assoc)
+    }
+
+    const dedupedGroup = Array.from(uniqueAssociationsMap.values())
+
+    return dedupedGroup
+  })
+}
diff --git a/packages/destination-actions/src/destinations/hubspot/upsertObject/index.ts b/packages/destination-actions/src/destinations/hubspot/upsertObject/index.ts
index 8832d4a117..7209197f70 100644
--- a/packages/destination-actions/src/destinations/hubspot/upsertObject/index.ts
+++ b/packages/destination-actions/src/destinations/hubspot/upsertObject/index.ts
@@ -7,7 +7,12 @@ import { Client } from './client'
 import { AssociationSyncMode, SyncMode, SchemaMatch, RequestData } from './types'
 import { dynamicFields } from './functions/dynamic-field-functions'
 import { getSchemaFromCache, saveSchemaToCache } from './functions/cache-functions'
-import { ensureValidTimestamps, mergeAndDeduplicateById, validate } from './functions/validation-functions'
+import {
+  deDuplicateAssociations,
+  ensureValidTimestamps,
+  mergeAndDeduplicateById,
+  validate
+} from './functions/validation-functions'
 import { objectSchema, compareSchemas } from './functions/schema-functions'
 import { sendFromRecords } from './functions/hubspot-record-functions'
 import { getListName, ensureList, sendLists } from './functions/hubspot-list-functions'
@@ -115,7 +120,8 @@ const send = async (
   }
 
   const fromRecordPayloads = await sendFromRecords(client, validPayloads, objectType, syncMode)
-  const associationPayloads = createAssociationPayloads(fromRecordPayloads, 'associations')
+  let associationPayloads = createAssociationPayloads(fromRecordPayloads, 'associations')
+  associationPayloads = deDuplicateAssociations(associationPayloads)
   const associatedRecords = await sendAssociatedRecords(
     client,
     associationPayloads,