diff --git a/src/math/Matrices/Matrix.js b/src/math/Matrices/Matrix.js
index e7d9748904..18545759bb 100644
--- a/src/math/Matrices/Matrix.js
+++ b/src/math/Matrices/Matrix.js
@@ -23,6 +23,9 @@ if (typeof Float32Array !== 'undefined') {
 export class Matrix extends MatrixInterface {
   matrix;
   #sqDimention;
+  // Duck-typing flag (like isVector / isColor) so code such as
+  // p5.Shader.setUniform can recognize a p5.Matrix without instanceof
+  isMatrix = true;
 
   constructor(...args) {
     super(...args);
diff --git a/src/strands/strands_api.js b/src/strands/strands_api.js
index 2ebbde4168..efe4639b33 100644
--- a/src/strands/strands_api.js
+++ b/src/strands/strands_api.js
@@ -934,6 +934,9 @@ export function initGlobalStrandsAPI(p5, fn, strandsContext) {
         typeAliases.push('Texture');
       } else if (/^vec/.test(typeInfo.fnName)) {
         typeAliases.push(pascalTypeName.replace('Vec', 'Vector'));
+      } else if (/^mat\dx\d$/.test(typeInfo.fnName)) {
+        // mat3x3 -> Mat3, so uniformMat3() works alongside uniformMat3x3()
+        typeAliases.push(pascalTypeName.slice(0, 4));
       }
     }
     augmentFn(
diff --git a/src/webgl/p5.Shader.js b/src/webgl/p5.Shader.js
index 68dbba20bf..ef055744d4 100644
--- a/src/webgl/p5.Shader.js
+++ b/src/webgl/p5.Shader.js
@@ -1164,6 +1164,8 @@ class Shader {
           : data.values;
     } else if (data?.isColor) {
       data = data._getRGBA([1, 1, 1, 1]);
+    } else if (data?.isMatrix) {
+      data = data.matrix;
     }
 
     if (uniform.isArray) {
diff --git a/test/unit/webgl/p5.Shader.js b/test/unit/webgl/p5.Shader.js
index ec3c0c8d28..dce8456271 100644
--- a/test/unit/webgl/p5.Shader.js
+++ b/test/unit/webgl/p5.Shader.js
@@ -3815,6 +3815,60 @@ suite('p5.Shader', function () {
         );
       }).not.toThrow();
     });
+
+
+    suite('matrix uniforms (#8992)', () => {
+      test('short aliases declare the same uniforms as the NxN names', () => {
+        myp5.createCanvas(5, 5, myp5.WEBGL);
+        const testShader = myp5.baseMaterialShader().modify(
+          () => {
+            myp5.uniformMat2('uShort2');
+            myp5.uniformMat3('uShort3');
+            myp5.uniformMat4('uShort4');
+            myp5.uniformMat3x3('uLong3');
+          },
+          { myp5 }
+        );
+
+        expect(() => {
+          myp5.shader(testShader);
+          myp5.plane(myp5.width, myp5.height);
+        }).not.toThrowError();
+
+        const src = testShader.fragSrc();
+        assert.include(src, 'uniform mat2x2 uShort2;');
+        assert.include(src, 'uniform mat3x3 uShort3;');
+        assert.include(src, 'uniform mat4x4 uShort4;');
+        assert.include(src, 'uniform mat3x3 uLong3;');
+      });
+
+      test('setUniform accepts a p5.Matrix', () => {
+        myp5.createCanvas(50, 50, myp5.WEBGL);
+        const testShader = myp5.createFilterShader(`
+          precision highp float;
+          uniform mat3 uM;
+          void main() {
+            gl_FragColor = vec4(uM[0][0], uM[1][0], uM[2][2], 1.0);
+          }
+        `);
+
+        // Column-major: index 3 is column 1, row 0 -> uM[1][0]
+        const m = myp5.createMatrix([
+          1.0, 0.0, 0.0,
+          0.5, 0.0, 0.0,
+          0.0, 0.0, 0.25
+        ]);
+
+        myp5.background(0);
+        testShader.setUniform('uM', m);
+        myp5.filter(testShader);
+
+        const pixelColor = myp5.get(25, 25);
+        assert.approximately(pixelColor[0], 255, 5); // uM[0][0] = 1.0
+        assert.approximately(pixelColor[1], 128, 5); // uM[1][0] = 0.5
+        assert.approximately(pixelColor[2], 64, 5); // uM[2][2] = 0.25
+      });
+  });
   });
 
   suite('p5.strands error messages', () => {
diff --git a/test/unit/webgpu/p5.Shader.js b/test/unit/webgpu/p5.Shader.js
index 4003152397..aaa86639ce 100644
--- a/test/unit/webgpu/p5.Shader.js
+++ b/test/unit/webgpu/p5.Shader.js
@@ -2145,5 +2145,26 @@ suite('WebGPU p5.Shader', function () {
         }).not.toThrow();
       });
     });
+
+    suite('matrix uniforms (#8992)', () => {
+      test('short aliases declare the same uniforms as the NxN names', async () => {
+        await myp5.createCanvas(5, 5, myp5.WEBGPU);
+        const testShader = myp5.baseMaterialShader().modify(
+          () => {
+            myp5.uniformMat2('uShort2');
+            myp5.uniformMat3('uShort3');
+            myp5.uniformMat4('uShort4');
+            myp5.uniformMat3x3('uLong3');
+          },
+          { myp5 }
+        );
+
+        const src = testShader.vertSrc();
+        assert.include(src, 'uShort2: mat2x2<f32>');
+        assert.include(src, 'uShort3: mat3x3<f32>');
+        assert.include(src, 'uShort4: mat4x4<f32>');
+        assert.include(src, 'uLong3: mat3x3<f32>');
+      });
+    });
   });
 });
diff --git a/utils/typescript.mjs b/utils/typescript.mjs
index e0a850e3d7..919d1f9a17 100644
--- a/utils/typescript.mjs
+++ b/utils/typescript.mjs
@@ -134,6 +134,9 @@ function processStrandsFunctions() {
         typeAliases.push('Texture');
       } else if (/^vec/.test(typeInfo.fnName)) {
         typeAliases.push(pascalTypeName.replace('Vec', 'Vector'));
+      } else if (/^mat\dx\d$/.test(typeInfo.fnName)) {
+        // mat3x3 -> Mat3, so uniformMat3() works alongside uniformMat3x3()
+        typeAliases.push(pascalTypeName.slice(0, 4));
       }
     }