diff --git a/CHANGELOG.md b/CHANGELOG.md
index dc74a2d3..c32538bf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changes
 
+- Use generic ledger type in ZOwnablePKWitnesses (#389)
 - Bump compact compiler to v0.29.0 (#366)
 
 ## 0.0.1-alpha.1 (2025-12-2)
diff --git a/contracts/src/access/test/simulators/ZOwnablePKSimulator.ts b/contracts/src/access/test/simulators/ZOwnablePKSimulator.ts
index 5dd24cf9..b1227ee1 100644
--- a/contracts/src/access/test/simulators/ZOwnablePKSimulator.ts
+++ b/contracts/src/access/test/simulators/ZOwnablePKSimulator.ts
@@ -14,15 +14,16 @@ import {
   ZOwnablePKWitnesses,
 } from '../../witnesses/ZOwnablePKWitnesses.js';
 
-/**
- * Type constructor args
- */
+/** Type constructor args */
 type ZOwnablePKArgs = readonly [
   owner: Uint8Array,
   instanceSalt: Uint8Array,
   isInit: boolean,
 ];
 
+/** Concrete ledger type extracted from the generated artifact */
+type ZOwnablePKLedger = ReturnType<typeof ledger>;
+
 /**
  * Base simulator
  * @dev We deliberately use `any` as the base simulator type.
@@ -47,7 +48,7 @@ const ZOwnablePKSimulatorBase: any = createSimulator<
     return [owner, instanceSalt, isInit];
   },
   ledgerExtractor: (state) => ledger(state),
-  witnessesFactory: () => ZOwnablePKWitnesses(),
+  witnessesFactory: () => ZOwnablePKWitnesses<ZOwnablePKLedger>(),
 });
 
 /**
diff --git a/contracts/src/access/witnesses/ZOwnablePKWitnesses.ts b/contracts/src/access/witnesses/ZOwnablePKWitnesses.ts
index 6453011d..61269a2a 100644
--- a/contracts/src/access/witnesses/ZOwnablePKWitnesses.ts
+++ b/contracts/src/access/witnesses/ZOwnablePKWitnesses.ts
@@ -1,18 +1,18 @@
 import { getRandomValues } from 'node:crypto';
 import type { WitnessContext } from '@midnight-ntwrk/compact-runtime';
-import type { Ledger } from '../../../artifacts/MockZOwnablePK/contract/index.js';
 
 /**
  * @description Interface defining the witness methods for ZOwnablePK operations.
+ * @template L - The ledger type.
  * @template P - The private state type.
  */
-export interface IZOwnablePKWitnesses<P> {
+export interface IZOwnablePKWitnesses<L, P> {
   /**
    * Retrieves the secret nonce from the private state.
-   * @param context - The witness context containing the private state.
+   * @param context - The witness context containing the ledger and private state.
    * @returns A tuple of the private state and the secret nonce as a Uint8Array.
    */
-  wit_secretNonce(context: WitnessContext<Ledger, P>): [P, Uint8Array];
+  wit_secretNonce(context: WitnessContext<L, P>): [P, Uint8Array];
 }
 
 /**
@@ -56,13 +56,16 @@ export const ZOwnablePKPrivateState = {
 
 /**
  * @description Factory function creating witness implementations for Ownable operations.
+ * @template L - The ledger type, supplied by the simulator.
  * @returns An object implementing the Witnesses interface for ZOwnablePKPrivateState.
  */
-export const ZOwnablePKWitnesses =
-  (): IZOwnablePKWitnesses<ZOwnablePKPrivateState> => ({
-    wit_secretNonce(
-      context: WitnessContext<Ledger, ZOwnablePKPrivateState>,
-    ): [ZOwnablePKPrivateState, Uint8Array] {
-      return [context.privateState, context.privateState.secretNonce];
-    },
-  });
+export const ZOwnablePKWitnesses = <L>(): IZOwnablePKWitnesses<
+  L,
+  ZOwnablePKPrivateState
+> => ({
+  wit_secretNonce(
+    context: WitnessContext<L, ZOwnablePKPrivateState>,
+  ): [ZOwnablePKPrivateState, Uint8Array] {
+    return [context.privateState, context.privateState.secretNonce];
+  },
+});
diff --git a/packages/simulator/README.md b/packages/simulator/README.md
index fcfd3ec0..48b2b496 100644
--- a/packages/simulator/README.md
+++ b/packages/simulator/README.md
@@ -20,7 +20,10 @@ import { Contract, ledger } from './artifacts/MyContract/contract/index.js';
 // 1. Define your contract arguments type
 type MyContractArgs = readonly [owner: Uint8Array, value: bigint];
 
-// 2. Create the simulator
+// 2. Define the extracted ledger type
+type MyContractLedger = ReturnType<typeof ledger>;
+
+// 3. Create the simulator
 const MySimulator = createSimulator<
   MyPrivateState,
   ReturnType<typeof ledger>,
@@ -31,10 +34,10 @@ const MySimulator = createSimulator<
   defaultPrivateState: () => MyPrivateState.generate(),
   contractArgs: (owner, value) => [owner, value],
   ledgerExtractor: (state) => ledger(state),
-  witnessesFactory: () => MyWitnesses(),
+  witnessesFactory: () => MyWitnesses<MyContractLedger>(),
 });
 
-// 3. Use it!
+// 4. Use it!
 const sim = new MySimulator([ownerAddress, 100n], { coinPK: deployerPK });
 ```
 
@@ -52,6 +55,9 @@ import { MyContractWitnesses, MyContractPrivateState } from './MyContractWitness
 // Define contract constructor arguments as a tuple type
 type MyContractArgs = readonly [arg1: bigint, arg2: string];
 
+// Define the extracted ledger type
+type MyContractLedger = ReturnType<typeof ledger>;
+
 // Create the base simulator with full type information
 const MyContractSimulatorBase = createSimulator<
   MyContractPrivateState,                    // Private state type
@@ -63,7 +69,7 @@ const MyContractSimulatorBase = createSimulator<
   defaultPrivateState: () => MyContractPrivateState.generate(),
   contractArgs: (arg1, arg2) => [arg1, arg2],
   ledgerExtractor: (state) => ledger(state),
-  witnessesFactory: () => MyContractWitnesses(),  // Note: Must be a function!
+  witnessesFactory: () => MyContractWitnesses<MyContractLedger>(),  // Note: Must be a function!
 });
 ```
 
@@ -76,7 +82,7 @@ If the Compact contract has no witnesses:
 // Some Compact contract examples use:
 export const MyContractWitnesses = {};
 
-// But for the simulator, wrap it in a function:
+// But for the simulator, wrap it in a generic function:
 export const MyContractWitnesses = () => ({});
 ```
 
diff --git a/packages/simulator/test/fixtures/sample-contracts/witnesses/SampleZOwnableWitnesses.ts b/packages/simulator/test/fixtures/sample-contracts/witnesses/SampleZOwnableWitnesses.ts
index 464007f1..af447156 100644
--- a/packages/simulator/test/fixtures/sample-contracts/witnesses/SampleZOwnableWitnesses.ts
+++ b/packages/simulator/test/fixtures/sample-contracts/witnesses/SampleZOwnableWitnesses.ts
@@ -1,18 +1,18 @@
 import { getRandomValues } from 'node:crypto';
 import type { WitnessContext } from '@midnight-ntwrk/compact-runtime';
-import type { Ledger } from '../../artifacts/SampleZOwnable/contract/index.js';
 
 /**
  * @description Interface defining the witness methods for SampleZOwnable operations.
+ * @template L - The ledger type.
  * @template P - The private state type.
  */
-export interface ISampleZOwnableWitnesses<P> {
+export interface ISampleZOwnableWitnesses<L, P> {
   /**
    * Retrieves the secret nonce from the private state.
-   * @param context - The witness context containing the private state.
+   * @param context - The witness context containing the ledger and private state.
    * @returns A tuple of the private state and the secret nonce as a Uint8Array.
    */
-  secretNonce(context: WitnessContext<Ledger, P>): [P, Uint8Array];
+  secretNonce(context: WitnessContext<L, P>): [P, Uint8Array];
 }
 
 /**
@@ -56,13 +56,16 @@ export const SampleZOwnablePrivateState = {
 
 /**
  * @description Factory function creating witness implementations for Ownable operations.
+ * @template L - The ledger type, supplied by the simulator.
  * @returns An object implementing the Witnesses interface for SampleZOwnablePrivateState.
  */
-export const SampleZOwnableWitnesses =
-  (): ISampleZOwnableWitnesses<SampleZOwnablePrivateState> => ({
-    secretNonce(
-      context: WitnessContext<Ledger, SampleZOwnablePrivateState>,
-    ): [SampleZOwnablePrivateState, Uint8Array] {
-      return [context.privateState, context.privateState.secretNonce];
-    },
-  });
+export const SampleZOwnableWitnesses = <L>(): ISampleZOwnableWitnesses<
+  L,
+  SampleZOwnablePrivateState
+> => ({
+  secretNonce(
+    context: WitnessContext<L, SampleZOwnablePrivateState>,
+  ): [SampleZOwnablePrivateState, Uint8Array] {
+    return [context.privateState, context.privateState.secretNonce];
+  },
+});
diff --git a/packages/simulator/test/fixtures/sample-contracts/witnesses/WitnessWitnesses.ts b/packages/simulator/test/fixtures/sample-contracts/witnesses/WitnessWitnesses.ts
index 7795cdfc..47c8009f 100644
--- a/packages/simulator/test/fixtures/sample-contracts/witnesses/WitnessWitnesses.ts
+++ b/packages/simulator/test/fixtures/sample-contracts/witnesses/WitnessWitnesses.ts
@@ -1,6 +1,5 @@
 import { getRandomValues } from 'node:crypto';
 import type { WitnessContext } from '@midnight-ntwrk/compact-runtime';
-import type { Ledger } from '../../artifacts/Witness/contract/index.js';
 
 const randomBigInt = (bits: number): bigint => {
   const bytes = Math.ceil(bits / 8);
@@ -16,14 +15,14 @@ const randomBigInt = (bits: number): bigint => {
   return result % max;
 };
 
-export interface IWitnessWitnesses<P> {
-  wit_secretBytes(context: WitnessContext<Ledger, P>): [P, Uint8Array];
+export interface IWitnessWitnesses<L, P> {
+  wit_secretBytes(context: WitnessContext<L, P>): [P, Uint8Array];
   wit_secretFieldPlusArg(
-    context: WitnessContext<Ledger, P>,
+    context: WitnessContext<L, P>,
     arg: bigint,
   ): [P, bigint];
   wit_secretUintPlusArgs(
-    context: WitnessContext<Ledger, P>,
+    context: WitnessContext<L, P>,
     arg1: bigint,
     arg2: bigint,
   ): [P, bigint];
@@ -45,20 +44,23 @@ export const WitnessPrivateState = {
   },
 };
 
-export const WitnessWitnesses = (): IWitnessWitnesses<WitnessPrivateState> => ({
+export const WitnessWitnesses = <L>(): IWitnessWitnesses<
+  L,
+  WitnessPrivateState
+> => ({
   wit_secretBytes(
-    context: WitnessContext<Ledger, WitnessPrivateState>,
+    context: WitnessContext<L, WitnessPrivateState>,
   ): [WitnessPrivateState, Uint8Array] {
     return [context.privateState, context.privateState.secretBytes];
   },
   wit_secretFieldPlusArg(
-    context: WitnessContext<Ledger, WitnessPrivateState>,
+    context: WitnessContext<L, WitnessPrivateState>,
     arg: bigint,
   ): [WitnessPrivateState, bigint] {
     return [context.privateState, context.privateState.secretField + arg];
   },
   wit_secretUintPlusArgs(
-    context: WitnessContext<Ledger, WitnessPrivateState>,
+    context: WitnessContext<L, WitnessPrivateState>,
     arg1: bigint,
     arg2: bigint,
   ): [WitnessPrivateState, bigint] {
diff --git a/packages/simulator/test/integration/SampleZOwnableSimulator.ts b/packages/simulator/test/integration/SampleZOwnableSimulator.ts
index c288e259..e2e26f2f 100644
--- a/packages/simulator/test/integration/SampleZOwnableSimulator.ts
+++ b/packages/simulator/test/integration/SampleZOwnableSimulator.ts
@@ -11,14 +11,15 @@ import {
   SampleZOwnableWitnesses,
 } from '../fixtures/sample-contracts/witnesses/SampleZOwnableWitnesses';
 
-/**
- * Type constructor args
- */
+/** Type constructor args */
 type SampleZOwnableArgs = readonly [
   owner: Uint8Array,
   instanceSalt: Uint8Array,
 ];
 
+/** Concrete ledger type extracted from the generated artifact */
+type SampleZOwnableLedger = ReturnType<typeof ledger>;
+
 /**
  * Base simulator
  */
@@ -36,7 +37,7 @@ const SampleZOwnableSimulatorBase = createSimulator<
     return [owner, instanceSalt];
   },
   ledgerExtractor: (state) => ledger(state),
-  witnessesFactory: () => SampleZOwnableWitnesses(),
+  witnessesFactory: () => SampleZOwnableWitnesses<SampleZOwnableLedger>(),
 });
 
 /**
diff --git a/packages/simulator/test/integration/WitnessSimulator.ts b/packages/simulator/test/integration/WitnessSimulator.ts
index c5b07041..e03ac46f 100644
--- a/packages/simulator/test/integration/WitnessSimulator.ts
+++ b/packages/simulator/test/integration/WitnessSimulator.ts
@@ -8,11 +8,12 @@ import {
   WitnessWitnesses,
 } from '../fixtures/sample-contracts/witnesses/WitnessWitnesses';
 
-/**
- * Type constructor args
- */
+/** Type constructor args */
 type WitnessArgs = readonly [];
 
+/** Concrete ledger type extracted from the generated artifact */
+type WitnessLedger = ReturnType<typeof ledger>;
+
 /**
  * Base simulator
  */
@@ -30,7 +31,7 @@ const WitnessSimulatorBase = createSimulator<
     return [];
   },
   ledgerExtractor: (state) => ledger(state),
-  witnessesFactory: () => WitnessWitnesses(),
+  witnessesFactory: () => WitnessWitnesses<WitnessLedger>(),
 });
 
 /**