diff --git a/src/hooks/__tests__/optimisticMutations.test.ts b/src/hooks/__tests__/optimisticMutations.test.ts
index 21ea24d..bcc20a4 100644
--- a/src/hooks/__tests__/optimisticMutations.test.ts
+++ b/src/hooks/__tests__/optimisticMutations.test.ts
@@ -2,7 +2,7 @@ import { describe, it, expect, vi, beforeEach } from 'vitest'
 import { renderHook, act } from '@testing-library/react'
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { type ReactNode, createElement } from 'react'
-import { useSubmitVouch } from '../useOptimisticVouch'
+import { useSubmitVouch, useDeclineVouch } from '../useOptimisticVouch'
 import { useAddProduct, useUpdateProduct } from '../useOptimisticProduct'
 import { queryKeys } from '../../services/queryKeys'
 import type { VouchRequest, VendorProduct } from '../../types'
@@ -21,6 +21,12 @@ vi.mock('../../services/vouching.service', () => ({
       }
       return Promise.resolve()
     }),
+    declineVouch: vi.fn().mockImplementation((learnerAddress: string) => {
+      if (learnerAddress === 'FAIL_ADDRESS') {
+        return Promise.reject(new Error('Decline failed'))
+      }
+      return Promise.resolve({ id: 'v1', status: 'declined' })
+    }),
   },
 }))
 
@@ -99,6 +105,74 @@ describe('Optimistic Mutation Hooks', () => {
     })
   })
 
+  describe('useDeclineVouch', () => {
+    it('optimistically removes the request from cache and persists it on success', async () => {
+      const initialRequests: VouchRequest[] = [
+        {
+          id: 'req-1',
+          learnerAddress: 'G_LEARNER_1',
+          learnerWallet: 'G_LEARNER_1',
+          score: 80,
+          tier: 'Silver',
+          totalLoans: 2,
+          activeLoans: 1,
+          totalBorrowed: 500,
+          totalRepaid: 300,
+          loanAmount: 200,
+          purpose: 'Laptop',
+          requestedAt: '2026-01-01',
+          skills: ['Rust'],
+        },
+      ]
+
+      queryClient.setQueryData(queryKeys.vouches.requests(), initialRequests)
+
+      const { result } = renderHook(() => useDeclineVouch(), { wrapper })
+
+      await act(async () => {
+        await result.current.mutateAsync('G_LEARNER_1')
+      })
+
+      const cached = queryClient.getQueryData<VouchRequest[]>(queryKeys.vouches.requests())
+      expect(cached).toEqual([])
+    })
+
+    it('rolls back the optimistic removal when the request fails', async () => {
+      const initialRequests: VouchRequest[] = [
+        {
+          id: 'req-1',
+          learnerAddress: 'FAIL_ADDRESS',
+          learnerWallet: 'FAIL_ADDRESS',
+          score: 80,
+          tier: 'Silver',
+          totalLoans: 2,
+          activeLoans: 1,
+          totalBorrowed: 500,
+          totalRepaid: 300,
+          loanAmount: 200,
+          purpose: 'Laptop',
+          requestedAt: '2026-01-01',
+          skills: ['Rust'],
+        },
+      ]
+
+      queryClient.setQueryData(queryKeys.vouches.requests(), initialRequests)
+
+      const { result } = renderHook(() => useDeclineVouch(), { wrapper })
+
+      await act(async () => {
+        try {
+          await result.current.mutateAsync('FAIL_ADDRESS')
+        } catch {
+          // Expected rejection
+        }
+      })
+
+      const cached = queryClient.getQueryData<VouchRequest[]>(queryKeys.vouches.requests())
+      expect(cached).toEqual(initialRequests)
+    })
+  })
+
   describe('useAddProduct', () => {
     it('optimistically appends product and rolls back on failure', async () => {
       const initialProducts: VendorProduct[] = [
diff --git a/src/hooks/useOptimisticVouch.ts b/src/hooks/useOptimisticVouch.ts
index 3130fbe..7295953 100644
--- a/src/hooks/useOptimisticVouch.ts
+++ b/src/hooks/useOptimisticVouch.ts
@@ -49,6 +49,38 @@ export function useSubmitVouch() {
   })
 }
 
+export function useDeclineVouch() {
+  const queryClient = useQueryClient()
+
+  return useMutation({
+    mutationFn: (learnerAddress: string) => vouchingService.declineVouch(learnerAddress),
+    onMutate: async (learnerAddress: string) => {
+      await queryClient.cancelQueries({ queryKey: queryKeys.vouches.requests() })
+
+      const previousRequests = queryClient.getQueryData<VouchRequest[]>(
+        queryKeys.vouches.requests()
+      )
+
+      if (previousRequests) {
+        queryClient.setQueryData<VouchRequest[]>(
+          queryKeys.vouches.requests(),
+          previousRequests.filter((req) => req.learnerAddress !== learnerAddress)
+        )
+      }
+
+      return { previousRequests }
+    },
+    onError: (_err, _learnerAddress, context) => {
+      if (context?.previousRequests) {
+        queryClient.setQueryData(queryKeys.vouches.requests(), context.previousRequests)
+      }
+    },
+    onSettled: () => {
+      invalidateSubtree.vouches(queryClient)
+    },
+  })
+}
+
 export function useRevokeVouch() {
   const queryClient = useQueryClient()
 
diff --git a/src/pages/Vouch.tsx b/src/pages/Vouch.tsx
index ae6623b..704caf7 100644
--- a/src/pages/Vouch.tsx
+++ b/src/pages/Vouch.tsx
@@ -5,7 +5,7 @@ import { ClipboardList, ShieldCheck, Award, AlertTriangle, RotateCw, Clock, Doll
 import { signTransaction, isConnected, requestAccess } from '@stellar/freighter-api'
 import { vouchingService } from '../services/vouching.service'
 import { queryKeys } from '../services/queryKeys'
-import { useSubmitVouch, useRevokeVouch } from '../hooks/useOptimisticVouch'
+import { useSubmitVouch, useRevokeVouch, useDeclineVouch } from '../hooks/useOptimisticVouch'
 import { Card } from '../components/ui/Card'
 import { Button } from '../components/ui/Button'
 import { Badge } from '../components/ui/Badge'
@@ -113,6 +113,7 @@ export function Vouch() {
 
   const submitMutation = useSubmitVouch()
   const revokeMutation = useRevokeVouch()
+  const declineMutation = useDeclineVouch()
 
   const handleVouchConfirm = async () => {
     if (!previewRequest) return
@@ -164,10 +165,17 @@ export function Vouch() {
     }
   }
 
-  const handleDecline = async (id: string) => {
+  const handleDecline = (id: string) => {
     setDecliningId(id)
-    await new Promise((r) => setTimeout(r, 600))
-    setDecliningId(null)
+    declineMutation.mutate(id, {
+      onError: (error) => {
+        const message = error instanceof Error ? error.message : 'Failed to decline request.'
+        toast.error(message)
+      },
+      onSettled: () => {
+        setDecliningId(null)
+      },
+    })
   }
 
   const tabs = [
diff --git a/src/services/vouching.service.ts b/src/services/vouching.service.ts
index 351c2e1..36711a0 100644
--- a/src/services/vouching.service.ts
+++ b/src/services/vouching.service.ts
@@ -95,4 +95,12 @@ export const vouchingService = {
   revokeVouch: async (id: string): Promise<void> => {
     await api.delete(`/vouching/${id}`)
   },
+
+  // POST /vouching/decline — mentor declines a pending vouch request for a learner.
+  declineVouch: async (learnerAddress: string): Promise<VouchResponse> => {
+    const res = await api.post<VouchResponse>('/vouching/decline', {
+      learnerWallet: learnerAddress,
+    })
+    return res.data
+  },
 }