diff --git a/debian/files/opt/dupfinder/dupfinder-setup.sh b/debian/files/opt/dupfinder/dupfinder-setup.sh
index f7e758d..1181779 100644
--- a/debian/files/opt/dupfinder/dupfinder-setup.sh
+++ b/debian/files/opt/dupfinder/dupfinder-setup.sh
@@ -53,12 +53,45 @@ if ! docker compose version &>/dev/null; then
 fi
 ok "docker compose V2 available"
 
-# ── Check NVIDIA GPU ──────────────────────────────────────────────────────────
+# ── Check NVIDIA GPU + container toolkit ─────────────────────────────────────
 info "Checking GPU..."
 if command -v nvidia-smi &>/dev/null && nvidia-smi &>/dev/null; then
     GPU_NAME=$(nvidia-smi --query-gpu=name --format=csv,noheader 2>/dev/null | head -1)
     ok "NVIDIA GPU detected: $GPU_NAME"
-    GPU_AVAILABLE=true
+
+    # nvidia-container-toolkit is required for Docker GPU passthrough
+    if ! command -v nvidia-ctk &>/dev/null && ! dpkg -l nvidia-container-toolkit &>/dev/null 2>&1; then
+        echo ""
+        echo "    nvidia-container-toolkit is not installed."
+        echo "    Without it Docker cannot pass the GPU to the container."
+        echo "    Install with:"
+        echo ""
+        echo "      curl -fsSL https://nvidia.github.io/libnvidia-container/gpgkey | sudo gpg --dearmor -o /usr/share/keyrings/nvidia-container-toolkit-keyring.gpg"
+        echo "      curl -s -L https://nvidia.github.io/libnvidia-container/stable/deb/nvidia-container-toolkit.list | sed 's#deb https://#deb [signed-by=/usr/share/keyrings/nvidia-container-toolkit-keyring.gpg] https://#g' | sudo tee /etc/apt/sources.list.d/nvidia-container-toolkit.list"
+        echo "      sudo apt update && sudo apt install -y nvidia-container-toolkit"
+        echo "      sudo nvidia-ctk runtime configure --runtime=docker"
+        echo "      sudo systemctl restart docker"
+        echo ""
+        read -rp "    Install nvidia-container-toolkit now? (Y/n): " INST_CTK
+        if [[ "$INST_CTK" != "n" && "$INST_CTK" != "N" ]]; then
+            curl -fsSL https://nvidia.github.io/libnvidia-container/gpgkey \
+                | gpg --dearmor -o /usr/share/keyrings/nvidia-container-toolkit-keyring.gpg
+            curl -s -L https://nvidia.github.io/libnvidia-container/stable/deb/nvidia-container-toolkit.list \
+                | sed 's#deb https://#deb [signed-by=/usr/share/keyrings/nvidia-container-toolkit-keyring.gpg] https://#g' \
+                | tee /etc/apt/sources.list.d/nvidia-container-toolkit.list
+            apt update -qq && apt install -y nvidia-container-toolkit
+            nvidia-ctk runtime configure --runtime=docker
+            systemctl restart docker
+            ok "nvidia-container-toolkit installed and Docker restarted"
+        else
+            echo "    Skipping — GPU will not be available in Docker. You can re-run setup later."
+            GPU_AVAILABLE=false
+        fi
+    else
+        ok "nvidia-container-toolkit is present"
+    fi
+
+    [[ "$GPU_AVAILABLE" != "false" ]] && GPU_AVAILABLE=true
 else
     echo "    No NVIDIA GPU detected — will use CPU for perceptual hashing"
     GPU_AVAILABLE=false