diff --git a/types/three/src/core/Object3D.d.ts b/types/three/src/core/Object3D.d.ts
index 58ecc8b77..90cc73872 100644
--- a/types/three/src/core/Object3D.d.ts
+++ b/types/three/src/core/Object3D.d.ts
@@ -1,6 +1,6 @@
 import { AnimationClip, AnimationClipJSON } from "../animation/AnimationClip.js";
 import { Camera } from "../cameras/Camera.js";
-import { Material } from "../materials/Material.js";
+import { Material, MaterialJSON } from "../materials/Material.js";
 import { Euler } from "../math/Euler.js";
 import { Matrix3 } from "../math/Matrix3.js";
 import { Matrix4, Matrix4Tuple } from "../math/Matrix4.js";
@@ -49,7 +49,7 @@ export interface Object3DJSON {
 
 export interface JSONMeta {
     geometries: Record<string, BufferGeometryJSON>;
-    materials: Record<string, unknown>;
+    materials: Record<string, MaterialJSON>;
     textures: Record<string, TextureJSON>;
     images: Record<string, SourceJSON>;
     shapes: Record<string, unknown>;
diff --git a/types/three/src/materials/Material.d.ts b/types/three/src/materials/Material.d.ts
index c7ba90f55..25823c84a 100644
--- a/types/three/src/materials/Material.d.ts
+++ b/types/three/src/materials/Material.d.ts
@@ -4,7 +4,9 @@ import {
     BlendingDstFactor,
     BlendingEquation,
     BlendingSrcFactor,
+    Combine,
     DepthModes,
+    NormalMapTypes,
     PixelFormat,
     Side,
     StencilFunc,
@@ -12,13 +14,14 @@ import {
 } from "../constants.js";
 import { BufferGeometry } from "../core/BufferGeometry.js";
 import { EventDispatcher } from "../core/EventDispatcher.js";
-import { Object3D } from "../core/Object3D.js";
+import { JSONMeta, Object3D } from "../core/Object3D.js";
 import { Color, ColorRepresentation } from "../math/Color.js";
 import { Plane } from "../math/Plane.js";
 import { Group } from "../objects/Group.js";
 import { WebGLProgramParametersWithUniforms } from "../renderers/webgl/WebGLPrograms.js";
 import { WebGLRenderer } from "../renderers/WebGLRenderer.js";
 import { Scene } from "../scenes/Scene.js";
+import { EulerTuple, SourceJSON, TextureJSON, Vector2Tuple } from "../Three.js";
 
 export interface MaterialParameters {
     alphaHash?: boolean | undefined;
@@ -68,6 +71,165 @@ export interface MaterialParameters {
     userData?: Record<string, any> | undefined;
 }
 
+export interface MaterialJSON {
+    metadata: { version: number; type: string; generator: string };
+
+    uuid: string;
+    type: string;
+
+    name?: string;
+
+    color?: number;
+    roughness?: number;
+    metalness?: number;
+
+    sheen?: number;
+    sheenColor?: number;
+    sheenRoughness?: number;
+    emissive?: number;
+    emissiveIntensity?: number;
+
+    specular?: number;
+    specularIntensity?: number;
+    specularColor?: number;
+    shininess?: number;
+    clearcoat?: number;
+    clearcoatRoughness?: number;
+    clearcoatMap?: string;
+    clearcoatRoughnessMap?: string;
+    clearcoatNormalMap?: string;
+    clearcoatNormalScale?: Vector2Tuple;
+
+    dispersion?: number;
+
+    iridescence?: number;
+    iridescenceIOR?: number;
+    iridescenceThicknessRange?: number;
+    iridescenceMap?: string;
+    iridescenceThicknessMap?: string;
+
+    anisotropy?: number;
+    anisotropyRotation?: number;
+    anisotropyMap?: string;
+
+    map?: string;
+    matcap?: string;
+    alphaMap?: string;
+
+    lightMap?: string;
+    lightMapIntensity?: number;
+
+    aoMap?: string;
+    aoMapIntensity?: number;
+
+    bumpMap?: string;
+    bumpScale?: number;
+
+    normalMap?: string;
+    normalMapType?: NormalMapTypes;
+    normalScale?: Vector2Tuple;
+
+    displacementMap?: string;
+    displacementScale?: number;
+    displacementBias?: number;
+
+    roughnessMap?: string;
+    metalnessMap?: string;
+
+    emissiveMap?: string;
+    specularMap?: string;
+    specularIntensityMap?: string;
+    specularColorMap?: string;
+
+    envMap?: string;
+    combine?: Combine;
+
+    envMapRotation?: EulerTuple;
+    envMapIntensity?: number;
+    reflectivity?: number;
+    refractionRatio?: number;
+
+    gradientMap?: string;
+
+    transmission?: number;
+    transmissionMap?: string;
+    thickness?: number;
+    thicknessMap?: string;
+    attenuationDistance?: number;
+    attenuationColor?: number;
+
+    size?: number;
+    shadowSide?: number;
+    sizeAttenuation?: boolean;
+
+    blending?: Blending;
+    side?: Side;
+    vertexColors?: boolean;
+
+    opacity?: number;
+    transparent?: boolean;
+
+    blendSrc?: BlendingSrcFactor;
+    blendDst?: BlendingDstFactor;
+    blendEquation?: BlendingEquation;
+    blendSrcAlpha?: number | null;
+    blendDstAlpha?: number | null;
+    blendEquationAlpha?: number | null;
+    blendColor?: number;
+    blendAlpha?: number;
+
+    depthFunc?: DepthModes;
+    depthTest?: boolean;
+    depthWrite?: boolean;
+    colorWrite?: boolean;
+
+    stencilWriteMask?: number;
+    stencilFunc?: StencilFunc;
+    stencilRef?: number;
+    stencilFuncMask?: number;
+    stencilFail?: StencilOp;
+    stencilZFail?: StencilOp;
+    stencilZPass?: StencilOp;
+    stencilWrite?: boolean;
+
+    rotation?: number;
+
+    polygonOffset?: boolean;
+    polygonOffsetFactor?: number;
+    polygonOffsetUnits?: number;
+
+    linewidth?: number;
+    dashSize?: number;
+    gapSize?: number;
+    scale?: number;
+
+    dithering?: boolean;
+
+    alphaTest?: number;
+    alphaHash?: boolean;
+    alphaToCoverage?: boolean;
+    premultipliedAlpha?: boolean;
+    forceSinglePass?: boolean;
+
+    wireframe?: boolean;
+    wireframeLinewidth?: number;
+    wireframeLinecap?: string;
+    wireframeLinejoin?: string;
+
+    flatShading?: boolean;
+
+    visible?: boolean;
+
+    toneMapped?: boolean;
+
+    fog?: boolean;
+
+    userData?: Record<string, unknown>;
+
+    textures?: Array<Omit<TextureJSON, "metadata">>;
+    images?: SourceJSON[];
+}
+
 /**
  * Materials describe the appearance of objects. They are defined in a (mostly) renderer-independent way, so you don't have to rewrite materials if you decide to use a different renderer.
  */
@@ -418,7 +580,7 @@ export class Material extends EventDispatcher<{ dispose: {} }> {
      * Convert the material to three.js JSON format.
      * @param meta Object containing metadata such as textures or images for the material.
      */
-    toJSON(meta?: any): any;
+    toJSON(meta?: JSONMeta): MaterialJSON;
 
     /**
      * Return a new material with the same parameters as this material.
diff --git a/types/three/src/materials/ShaderMaterial.d.ts b/types/three/src/materials/ShaderMaterial.d.ts
index 6a940c07a..671b3e2c3 100644
--- a/types/three/src/materials/ShaderMaterial.d.ts
+++ b/types/three/src/materials/ShaderMaterial.d.ts
@@ -1,7 +1,13 @@
 import { GLSLVersion } from "../constants.js";
+import { JSONMeta } from "../core/Object3D.js";
 import { UniformsGroup } from "../core/UniformsGroup.js";
+import { Matrix3, Matrix3Tuple } from "../math/Matrix3.js";
+import { Matrix4, Matrix4Tuple } from "../math/Matrix4.js";
+import { Vector2Tuple } from "../math/Vector2.js";
+import { Vector3Tuple } from "../math/Vector3.js";
+import { Vector4Tuple } from "../math/Vector4.js";
 import { IUniform } from "../renderers/shaders/UniformsLib.js";
-import { Material, MaterialParameters } from "./Material.js";
+import { Material, MaterialJSON, MaterialParameters } from "./Material.js";
 
 export interface ShaderMaterialParameters extends MaterialParameters {
     uniforms?: { [uniform: string]: IUniform } | undefined;
@@ -23,6 +29,46 @@ export interface ShaderMaterialParameters extends MaterialParameters {
     glslVersion?: GLSLVersion | undefined;
 }
 
+export type ShaderMaterialUniformJSON = {
+    type: "t";
+    value: string;
+} | {
+    type: "c";
+    value: number;
+} | {
+    type: "v2";
+    value: Vector2Tuple;
+} | {
+    type: "v3";
+    value: Vector3Tuple;
+} | {
+    type: "v4";
+    value: Vector4Tuple;
+} | {
+    type: "m3";
+    value: Matrix3Tuple;
+} | {
+    type: "m4";
+    value: Matrix4Tuple;
+} | {
+    value: unknown;
+};
+
+export interface ShaderMaterialJSON extends MaterialJSON {
+    glslVersion: number | null;
+    uniforms: Record<string, ShaderMaterialUniformJSON>;
+
+    defines?: Record<string, unknown>;
+
+    vertexShader: string;
+    ragmentShader: string;
+
+    lights: boolean;
+    clipping: boolean;
+
+    extensions?: Record<string, boolean>;
+}
+
 export class ShaderMaterial extends Material {
     constructor(parameters?: ShaderMaterialParameters);
 
@@ -116,5 +162,6 @@ export class ShaderMaterial extends Material {
     glslVersion: GLSLVersion | null;
 
     setValues(parameters: ShaderMaterialParameters): void;
-    toJSON(meta: any): any;
+
+    toJSON(meta?: JSONMeta): ShaderMaterialJSON;
 }