diff --git a/.github/workflows/linux-wasm-ci-build-and-test-workflow.yml b/.github/workflows/linux-wasm-ci-build-and-test-workflow.yml
index e08ce13c6dd33..4288442720493 100644
--- a/.github/workflows/linux-wasm-ci-build-and-test-workflow.yml
+++ b/.github/workflows/linux-wasm-ci-build-and-test-workflow.yml
@@ -50,6 +50,12 @@ jobs:
         --enable_wasm_simd
         ${{ inputs.enable_wasm_threads == true && '--enable_wasm_threads' || '' }}
         ${{ inputs.extra_build_args }}
+      reduced_size_build_args: >-
+        --disable_ml_ops
+        --disable_generation_ops
+        --disable_types string float4 float8 optional sparsetensor
+        --include_ops_by_config onnxruntime/wasm/reduced_types.config
+        --enable_reduced_operator_type_support
 
     steps:
       - name: Checkout code
@@ -68,6 +74,9 @@ jobs:
           python-version: "3.12"
           architecture: ${{ env.buildArch }}
 
+      - name: Install python dependencies
+        run: python -m pip install flatbuffers
+
       - uses: microsoft/onnxruntime-github-actions/setup-build-tools@v0.0.9
         with:
           vcpkg-version: '2025.08.27'
@@ -109,6 +118,7 @@ jobs:
             --use_webnn \
             --target onnxruntime_webassembly \
             ${{ inputs.build_config == 'Release' && '--enable_wasm_api_exception_catching' || '' }} \
+            ${{ env.reduced_size_build_args }} \
             --skip_tests
         working-directory: ${{ github.workspace }}
 
@@ -122,6 +132,7 @@ jobs:
             --use_webnn \
             --enable_wasm_jspi \
             --target onnxruntime_webassembly \
+            ${{ env.reduced_size_build_args }} \
             --skip_tests
         working-directory: ${{ github.workspace }}
 
diff --git a/js/build_jsep.bat b/js/build_jsep.bat
index ace96e978d934..fb94f0841ee01 100644
--- a/js/build_jsep.bat
+++ b/js/build_jsep.bat
@@ -64,8 +64,21 @@ popd
 
 set PATH=C:\Program Files\Git\usr\bin;%PATH%
 
-call %ROOT%build.bat --config %CONFIG% %CONFIG_EXTRA_FLAG% --skip_submodule_sync --build_wasm --skip_tests^
- --enable_wasm_simd --enable_wasm_threads --use_jsep --use_webnn --target onnxruntime_webassembly --build_dir %BUILD_DIR%
+call %ROOT%build.bat^
+ --config %CONFIG%^
+ %CONFIG_EXTRA_FLAG%^
+ --parallel^
+ --skip_submodule_sync^
+ --build_wasm^
+ --target onnxruntime_webassembly^
+ --skip_tests^
+ --enable_wasm_simd^
+ --enable_wasm_threads^
+ --use_jsep^
+ --use_webnn^
+ --build_dir %BUILD_DIR%^
+ --include_ops_by_config %ROOT%onnxruntime\wasm\reduced_types.config^
+ --enable_reduced_operator_type_support
 
 IF NOT "%ERRORLEVEL%" == "0" (
   exit /b %ERRORLEVEL%
diff --git a/js/build_webgpu.bat b/js/build_webgpu.bat
index d32a7ab1abb81..5d017edbfa22b 100644
--- a/js/build_webgpu.bat
+++ b/js/build_webgpu.bat
@@ -68,8 +68,22 @@ popd
 
 set PATH=C:\Program Files\Git\usr\bin;%PATH%
 
-call %ROOT%build.bat --config %CONFIG% %CONFIG_EXTRA_FLAG% --skip_submodule_sync --build_wasm --target onnxruntime_webassembly --skip_tests^
- --enable_wasm_simd --enable_wasm_threads --use_webnn --use_webgpu --enable_wasm_jspi --build_dir %BUILD_DIR%
+call %ROOT%build.bat^
+ --config %CONFIG%^
+ %CONFIG_EXTRA_FLAG%^
+ --parallel^
+ --skip_submodule_sync^
+ --build_wasm^
+ --target onnxruntime_webassembly^
+ --skip_tests^
+ --enable_wasm_simd^
+ --enable_wasm_threads^
+ --use_webnn^
+ --use_webgpu^
+ --enable_wasm_jspi^
+ --build_dir %BUILD_DIR%^
+ --include_ops_by_config %ROOT%onnxruntime\wasm\reduced_types.config^
+ --enable_reduced_operator_type_support
 
 IF NOT "%ERRORLEVEL%" == "0" (
   exit /b %ERRORLEVEL%
diff --git a/js/build_webgpu.sh b/js/build_webgpu.sh
index ea12093c37cf7..1e9492d818680 100755
--- a/js/build_webgpu.sh
+++ b/js/build_webgpu.sh
@@ -101,7 +101,9 @@ echo "Calling $ROOT_DIR/build.sh to build WebAssembly..."
     --use_webnn \
     --use_webgpu \
     --enable_wasm_jspi \
-    --build_dir "$BUILD_DIR"
+    --build_dir "$BUILD_DIR" \
+    --include_ops_by_config "$ROOT_DIR/onnxruntime/wasm/reduced_types.config" \
+    --enable_reduced_operator_type_support
 
 # The 'set -e' command at the beginning of the script ensures that the script will exit
 # immediately if the build.sh command (or any other command) fails.
diff --git a/onnxruntime/wasm/reduced_types.config b/onnxruntime/wasm/reduced_types.config
new file mode 100644
index 0000000000000..5e5ced7e759f4
--- /dev/null
+++ b/onnxruntime/wasm/reduced_types.config
@@ -0,0 +1,14 @@
+# Reduced type configuration for WebAssembly builds.
+# This limits globally allowed types for all operators to reduce binary size (~230KB).
+# See https://onnxruntime.ai/docs/reference/operators/reduced-operator-config-file.html
+#
+# Usage: pass to build.py via:
+#   --include_ops_by_config onnxruntime/wasm/reduced_types.config --enable_reduced_operator_type_support
+#
+# Excluded types: float4, float8, float64 (double), int16, uint16
+
+# Keep all operators - only apply type reduction
+!no_ops_specified_means_all_ops_are_required
+
+# Globally allowed types for all operators
+!globally_allowed_types;bool,int8_t,uint8_t,int32_t,uint32_t,int64_t,uint64_t,float,MLFloat16
diff --git a/tools/ci_build/github/azure-pipelines/templates/linux-wasm-ci.yml b/tools/ci_build/github/azure-pipelines/templates/linux-wasm-ci.yml
index ef30a49b0fb83..97e7a43a88824 100644
--- a/tools/ci_build/github/azure-pipelines/templates/linux-wasm-ci.yml
+++ b/tools/ci_build/github/azure-pipelines/templates/linux-wasm-ci.yml
@@ -57,6 +57,7 @@ jobs:
       ExceptionHandlingBuildArgs: '--enable_wasm_api_exception_catching'
     ${{ else }}:
       ExceptionHandlingBuildArgs: ''
+    reducedSizeBuildArgs: '--disable_ml_ops --disable_generation_ops --disable_types string float4 float8 optional sparsetensor --include_ops_by_config $(Build.SourcesDirectory)/onnxruntime/wasm/reduced_types.config --enable_reduced_operator_type_support'
     runCodesignValidationInjection: false
     TODAY: $[format('{0:dd}{0:MM}{0:yyyy}', pipeline.startTime)]
     ORT_CACHE_DIR: $(Agent.TempDirectory)/ort_ccache
@@ -92,6 +93,9 @@ jobs:
     inputs:
       versionSpec: '22.x'
 
+  - script: python -m pip install flatbuffers
+    displayName: 'Install python dependencies'
+
   - ${{if eq(parameters.WithCache, true)}}:
     - script: |
         set -ex
@@ -141,7 +145,7 @@ jobs:
         ${{ else }}:
           AdditionalKey: wasm_inferencing_webgpu | ${{ parameters.BuildConfig }}
         CacheDir: $(ORT_CACHE_DIR)/wasm_inferencing_webgpu
-        Arguments: '$(CommonBuildArgs) --build_dir $(Build.BinariesDirectory)/wasm_inferencing_webgpu --use_webgpu --use_webnn --target onnxruntime_webassembly $(ExceptionHandlingBuildArgs) --skip_tests'
+        Arguments: '$(CommonBuildArgs) --build_dir $(Build.BinariesDirectory)/wasm_inferencing_webgpu --use_webgpu --use_webnn --target onnxruntime_webassembly $(ExceptionHandlingBuildArgs) $(reducedSizeBuildArgs) --skip_tests'
         DisplayName: 'Build (simd + threads + WebGPU experimental)'
         WithCache: ${{ parameters.WithCache }}
 
@@ -154,7 +158,7 @@ jobs:
         ${{ else }}:
           AdditionalKey: wasm_inferencing_webgpu_jspi | ${{ parameters.BuildConfig }}
         CacheDir: $(ORT_CACHE_DIR)/wasm_inferencing_webgpu_jspi
-        Arguments: '$(CommonBuildArgs) --build_dir $(Build.BinariesDirectory)/wasm_inferencing_webgpu_jspi --use_webgpu --use_webnn --enable_wasm_jspi --target onnxruntime_webassembly --skip_tests'
+        Arguments: '$(CommonBuildArgs) --build_dir $(Build.BinariesDirectory)/wasm_inferencing_webgpu_jspi --use_webgpu --use_webnn --enable_wasm_jspi --target onnxruntime_webassembly $(reducedSizeBuildArgs) --skip_tests'
         DisplayName: 'Build (simd + threads + WebGPU experimental, JSPI)'
         WithCache: ${{ parameters.WithCache }}