diff --git a/src/InvocationModel.ts b/src/InvocationModel.ts
index d1958aed..62ba8408 100644
--- a/src/InvocationModel.ts
+++ b/src/InvocationModel.ts
@@ -23,6 +23,7 @@ import { toRpcTypedData } from './converters/toRpcTypedData';
 import { AzFuncSystemError } from './errors';
 import { waitForProxyRequest } from './http/httpProxy';
 import { createStreamRequest } from './http/HttpRequest';
+import { HttpResponse } from './http/HttpResponse';
 import { InvocationContext } from './InvocationContext';
 import { enableHttpStream } from './setup';
 import { isHttpTrigger, isTimerTrigger, isTrigger } from './utils/isTrigger';
@@ -105,7 +106,33 @@ export class InvocationModel implements coreTypes.InvocationModel {
     ): Promise<unknown> {
         try {
             return await Promise.resolve(handler(...inputs, context));
+        } catch (error) {
+            // Log the error for debugging purposes
+            const errorMessage = error instanceof Error ? error.message : String(error);
+            this.#systemLog('error', `Function threw an error: ${errorMessage}`);
+
+            // For HTTP triggers with streaming enabled, convert errors to HTTP responses
+            if (isHttpTrigger(this.#triggerType) && enableHttpStream) {
+                const statusCode = this.#getErrorStatusCode(error);
+                const responseBody = {
+                    error: errorMessage,
+                    timestamp: new Date().toISOString(),
+                    invocationId: context.invocationId,
+                };
+
+                return new HttpResponse({
+                    status: statusCode,
+                    jsonBody: responseBody,
+                    headers: {
+                        'Content-Type': 'application/json',
+                    },
+                });
+            }
+
+            // For non-HTTP triggers or when streaming is disabled, re-throw the original error
+            throw error;
         } finally {
+            // Mark invocation as done regardless of success or failure
             this.#isDone = true;
         }
     }
@@ -173,4 +200,43 @@ export class InvocationModel implements coreTypes.InvocationModel {
         }
         this.#log(level, 'user', ...args);
     }
+
+    /**
+     * Maps different types of errors to appropriate HTTP status codes
+     * @param error The error to analyze
+     * @returns HTTP status code
+     */
+    #getErrorStatusCode(error: unknown): number {
+        const errorMessage = error instanceof Error ? error.message.toLowerCase() : String(error).toLowerCase();
+
+        // Check for specific error patterns and map to appropriate status codes
+        if (errorMessage.includes('unauthorized') || errorMessage.includes('auth')) {
+            return 401;
+        }
+        if (errorMessage.includes('forbidden') || errorMessage.includes('access denied')) {
+            return 403;
+        }
+        if (errorMessage.includes('not found') || errorMessage.includes('404')) {
+            return 404;
+        }
+        if (
+            errorMessage.includes('bad request') ||
+            errorMessage.includes('invalid') ||
+            errorMessage.includes('validation')
+        ) {
+            return 400;
+        }
+        if (errorMessage.includes('timeout') || errorMessage.includes('timed out')) {
+            return 408;
+        }
+        if (errorMessage.includes('conflict')) {
+            return 409;
+        }
+        if (errorMessage.includes('too many requests') || errorMessage.includes('rate limit')) {
+            return 429;
+        }
+
+        // Default to 500 Internal Server Error for unrecognized errors
+        return 500;
+    }
 }
diff --git a/test/http-streaming-error-handling.test.ts b/test/http-streaming-error-handling.test.ts
new file mode 100644
index 00000000..a82b3763
--- /dev/null
+++ b/test/http-streaming-error-handling.test.ts
@@ -0,0 +1,312 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License.
+
+import 'mocha';
+import { expect } from 'chai';
+import { HttpResponse } from '../src/http/HttpResponse';
+import { InvocationContext } from '../src/InvocationContext';
+import { InvocationModel } from '../src/InvocationModel';
+import { enableHttpStream, setup } from '../src/setup';
+
+describe('HTTP Streaming Error Handling', () => {
+    let originalEnableHttpStream: boolean;
+
+    before(() => {
+        originalEnableHttpStream = enableHttpStream;
+    });
+
+    afterEach(() => {
+        // Reset to original state
+        setup({ enableHttpStream: originalEnableHttpStream });
+    });
+
+    it('should convert validation errors to HTTP 400 responses in streaming mode', async () => {
+        // Enable HTTP streaming for this test
+        setup({ enableHttpStream: true });
+
+        // Create a mock HTTP trigger invocation model
+        const mockCoreCtx = {
+            invocationId: 'test-invocation-123',
+            request: {
+                inputData: [],
+                triggerMetadata: {},
+            },
+            metadata: {
+                name: 'testHttpFunction',
+                bindings: {
+                    httpTrigger: { type: 'httpTrigger', direction: 'in' },
+                },
+            },
+            log: () => {},
+            state: undefined,
+        };
+
+        const invocationModel = new InvocationModel(mockCoreCtx as any);
+
+        // Create a mock context
+        const context = new InvocationContext({
+            invocationId: 'test-invocation-123',
+            functionName: 'testHttpFunction',
+            logHandler: () => {},
+            retryContext: undefined,
+            traceContext: undefined,
+            triggerMetadata: {},
+            options: {},
+        });
+
+        // Create a handler that throws a validation error
+        const errorHandler = () => {
+            throw new Error('Invalid input parameters provided');
+        };
+
+        // Should convert error to HTTP response instead of throwing
+        const result = await invocationModel.invokeFunction(context, [], errorHandler);
+
+        expect(result).to.be.instanceOf(HttpResponse);
+        const httpResponse = result as HttpResponse;
+        expect(httpResponse.status).to.equal(400);
+
+        const responseBody = (await httpResponse.json()) as any;
+        expect(responseBody).to.have.property('error', 'Invalid input parameters provided');
+        expect(responseBody).to.have.property('timestamp');
+        expect(responseBody).to.have.property('invocationId', 'test-invocation-123');
+    });
+
+    it('should convert unauthorized errors to HTTP 401 responses in streaming mode', async () => {
+        setup({ enableHttpStream: true });
+
+        const mockCoreCtx = {
+            invocationId: 'test-invocation-456',
+            request: { inputData: [], triggerMetadata: {} },
+            metadata: {
+                name: 'testHttpFunction',
+                bindings: { httpTrigger: { type: 'httpTrigger', direction: 'in' } },
+            },
+            log: () => {},
+            state: undefined,
+        };
+
+        const invocationModel = new InvocationModel(mockCoreCtx as any);
+        const context = new InvocationContext({
+            invocationId: 'test-invocation-456',
+            functionName: 'testHttpFunction',
+            logHandler: () => {},
+            retryContext: undefined,
+            traceContext: undefined,
+            triggerMetadata: {},
+            options: {},
+        });
+
+        const errorHandler = () => {
+            throw new Error('Unauthorized access to resource');
+        };
+
+        // Should convert error to HTTP 401 response
+        const result = await invocationModel.invokeFunction(context, [], errorHandler);
+
+        expect(result).to.be.instanceOf(HttpResponse);
+        const httpResponse = result as HttpResponse;
+        expect(httpResponse.status).to.equal(401);
+
+        const responseBody = (await httpResponse.json()) as any;
+        expect(responseBody.error).to.equal('Unauthorized access to resource');
+    });
+
+    it('should convert system errors to HTTP 500 responses in streaming mode', async () => {
+        setup({ enableHttpStream: true });
+
+        const mockCoreCtx = {
+            invocationId: 'test-invocation-789',
+            request: { inputData: [], triggerMetadata: {} },
+            metadata: {
+                name: 'testHttpFunction',
+                bindings: { httpTrigger: { type: 'httpTrigger', direction: 'in' } },
+            },
+            log: () => {},
+            state: undefined,
+        };
+
+        const invocationModel = new InvocationModel(mockCoreCtx as any);
+        const context = new InvocationContext({
+            invocationId: 'test-invocation-789',
+            functionName: 'testHttpFunction',
+            logHandler: () => {},
+            retryContext: undefined,
+            traceContext: undefined,
+            triggerMetadata: {},
+            options: {},
+        });
+
+        const errorHandler = () => {
+            throw new Error('Database connection failed');
+        };
+
+        // Should convert system error to HTTP 500 response
+        const result = await invocationModel.invokeFunction(context, [], errorHandler);
+
+        expect(result).to.be.instanceOf(HttpResponse);
+        const httpResponse = result as HttpResponse;
+        expect(httpResponse.status).to.equal(500);
+
+        const responseBody = (await httpResponse.json()) as any;
+        expect(responseBody.error).to.equal('Database connection failed');
+        expect(responseBody.invocationId).to.equal('test-invocation-789');
+    });
+
+    it('should still throw errors for non-HTTP streaming mode', async () => {
+        // Disable HTTP streaming
+        setup({ enableHttpStream: false });
+
+        const mockCoreCtx = {
+            invocationId: 'test-invocation-000',
+            request: { inputData: [], triggerMetadata: {} },
+            metadata: {
+                name: 'testHttpFunction',
+                bindings: { httpTrigger: { type: 'httpTrigger', direction: 'in' } },
+            },
+            log: () => {},
+            state: undefined,
+        };
+
+        const invocationModel = new InvocationModel(mockCoreCtx as any);
+        const context = new InvocationContext({
+            invocationId: 'test-invocation-000',
+            functionName: 'testHttpFunction',
+            logHandler: () => {},
+            retryContext: undefined,
+            traceContext: undefined,
+            triggerMetadata: {},
+            options: {},
+        });
+
+        const errorHandler = () => {
+            throw new Error('Test error should be thrown');
+        };
+
+        // Should throw the error instead of converting to HttpResponse
+        await expect(invocationModel.invokeFunction(context, [], errorHandler)).to.be.rejectedWith(
+            'Test error should be thrown'
+        );
+    });
+
+    it('should still throw errors for non-HTTP triggers even with streaming enabled', async () => {
+        setup({ enableHttpStream: true });
+
+        // Create a non-HTTP trigger (timer trigger)
+        const mockCoreCtx = {
+            invocationId: 'test-invocation-timer',
+            request: { inputData: [], triggerMetadata: {} },
+            metadata: {
+                name: 'testTimerFunction',
+                bindings: { timerTrigger: { type: 'timerTrigger', direction: 'in' } },
+            },
+            log: () => {},
+            state: undefined,
+        };
+
+        const invocationModel = new InvocationModel(mockCoreCtx as any);
+        const context = new InvocationContext({
+            invocationId: 'test-invocation-timer',
+            functionName: 'testTimerFunction',
+            logHandler: () => {},
+            retryContext: undefined,
+            traceContext: undefined,
+            triggerMetadata: {},
+            options: {},
+        });
+
+        const errorHandler = () => {
+            throw new Error('Timer function error should be thrown');
+        };
+
+        // Should throw the error for non-HTTP triggers
+        await expect(invocationModel.invokeFunction(context, [], errorHandler)).to.be.rejectedWith(
+            'Timer function error should be thrown'
+        );
+    });
+
+    it('should set proper Content-Type headers in HTTP error responses', async () => {
+        setup({ enableHttpStream: true });
+
+        const mockCoreCtx = {
+            invocationId: 'test-content-type',
+            request: { inputData: [], triggerMetadata: {} },
+            metadata: {
+                name: 'testHttpFunction',
+                bindings: { httpTrigger: { type: 'httpTrigger', direction: 'in' } },
+            },
+            log: () => {},
+            state: undefined,
+        };
+
+        const invocationModel = new InvocationModel(mockCoreCtx as any);
+        const context = new InvocationContext({
+            invocationId: 'test-content-type',
+            functionName: 'testHttpFunction',
+            logHandler: () => {},
+            retryContext: undefined,
+            traceContext: undefined,
+            triggerMetadata: {},
+            options: {},
+        });
+
+        const errorHandler = () => {
+            throw new Error('Test error for headers');
+        };
+
+        const result = await invocationModel.invokeFunction(context, [], errorHandler);
+
+        expect(result).to.be.instanceOf(HttpResponse);
+        const httpResponse = result as HttpResponse;
+        expect(httpResponse.headers.get('Content-Type')).to.equal('application/json');
+    });
+
+    it('should handle different error types with appropriate status codes', async () => {
+        setup({ enableHttpStream: true });
+
+        const errorTestCases = [
+            { error: 'Not found resource', expectedStatus: 404 },
+            { error: 'Forbidden operation detected', expectedStatus: 403 },
+            { error: 'Request timeout happened', expectedStatus: 408 },
+            { error: 'Too many requests made', expectedStatus: 429 },
+            { error: 'Some random error', expectedStatus: 500 },
+        ];
+
+        for (const testCase of errorTestCases) {
+            const mockCoreCtx = {
+                invocationId: `test-${testCase.expectedStatus}`,
+                request: { inputData: [], triggerMetadata: {} },
+                metadata: {
+                    name: 'testHttpFunction',
+                    bindings: { httpTrigger: { type: 'httpTrigger', direction: 'in' } },
+                },
+                log: () => {},
+                state: undefined,
+            };
+
+            const invocationModel = new InvocationModel(mockCoreCtx as any);
+            const context = new InvocationContext({
+                invocationId: `test-${testCase.expectedStatus}`,
+                functionName: 'testHttpFunction',
+                logHandler: () => {},
+                retryContext: undefined,
+                traceContext: undefined,
+                triggerMetadata: {},
+                options: {},
+            });
+
+            const errorHandler = () => {
+                throw new Error(testCase.error);
+            };
+
+            const result = await invocationModel.invokeFunction(context, [], errorHandler);
+
+            expect(result).to.be.instanceOf(HttpResponse);
+            const httpResponse = result as HttpResponse;
+            expect(httpResponse.status).to.equal(testCase.expectedStatus);
+
+            const responseBody = (await httpResponse.json()) as any;
+            expect(responseBody.error).to.equal(testCase.error);
+        }
+    });
+});