diff --git a/packages/http-client-js/src/components/http-request-parameters-expression.tsx b/packages/http-client-js/src/components/http-request-parameters-expression.tsx
index f38da9ec411..dc248bffb58 100644
--- a/packages/http-client-js/src/components/http-request-parameters-expression.tsx
+++ b/packages/http-client-js/src/components/http-request-parameters-expression.tsx
@@ -53,7 +53,7 @@ export function HttpRequestParametersExpression(props: HttpRequestParametersExpr
 
         if (propertyExpression.isNullish) {
           return code`
-        ...(${propertyExpression.fullExpression} && {${(<JsonTransform itemRef={propertyExpression.leadingExpression} type={httpProperty.property} target="transport" />)}})
+        ...(${propertyExpression.fullExpression} != undefined && {${(<JsonTransform itemRef={propertyExpression.leadingExpression} type={httpProperty.property} target="transport" />)}})
       `;
         } else {
           return (
diff --git a/packages/http-client-js/test/scenarios/encoding/header_bytes.md b/packages/http-client-js/test/scenarios/encoding/header_bytes.md
index 3bc1c915bd3..982d6ced1a2 100644
--- a/packages/http-client-js/test/scenarios/encoding/header_bytes.md
+++ b/packages/http-client-js/test/scenarios/encoding/header_bytes.md
@@ -68,7 +68,7 @@ export async function defaultEncoding(
   const path = parse("/default").expand({});
   const httpRequestOptions = {
     headers: {
-      ...(options?.value && {
+      ...(options?.value != undefined && {
         value: encodeUint8Array(options.value, "base64")!,
       }),
     },
diff --git a/packages/http-client-js/test/scenarios/encoding/header_date.md b/packages/http-client-js/test/scenarios/encoding/header_date.md
index f7ace86237f..b6be9b50be3 100644
--- a/packages/http-client-js/test/scenarios/encoding/header_date.md
+++ b/packages/http-client-js/test/scenarios/encoding/header_date.md
@@ -68,7 +68,9 @@ export async function defaultEncoding(
   const path = parse("/default").expand({});
   const httpRequestOptions = {
     headers: {
-      ...(options?.value && { value: dateRfc7231Serializer(options.value) }),
+      ...(options?.value != undefined && {
+        value: dateRfc7231Serializer(options.value),
+      }),
     },
   };
   const response = await client.pathUnchecked(path).get(httpRequestOptions);
diff --git a/packages/http-client-js/test/scenarios/encoding/query_date.md b/packages/http-client-js/test/scenarios/encoding/query_date.md
index bf3087b6951..284476a182f 100644
--- a/packages/http-client-js/test/scenarios/encoding/query_date.md
+++ b/packages/http-client-js/test/scenarios/encoding/query_date.md
@@ -66,7 +66,9 @@ export async function defaultEncoding(
   options?: DefaultEncodingOptions,
 ): Promise<void> {
   const path = parse("/default{?value}").expand({
-    ...(options?.value && { value: dateRfc3339Serializer(options.value) }),
+    ...(options?.value != undefined && {
+      value: dateRfc3339Serializer(options.value),
+    }),
   });
   const httpRequestOptions = {
     headers: {},
diff --git a/packages/http-client-js/test/scenarios/http-operations/basic-request.md b/packages/http-client-js/test/scenarios/http-operations/basic-request.md
index 939accf720b..0aabf26489b 100644
--- a/packages/http-client-js/test/scenarios/http-operations/basic-request.md
+++ b/packages/http-client-js/test/scenarios/http-operations/basic-request.md
@@ -142,3 +142,55 @@ export async function read(
   throw createRestError(response);
 }
 ```
+
+# Should preserve falsy optional HTTP parameters
+
+This test verifies optional query and header parameters are emitted when their value is falsy but present.
+
+## TypeSpec
+
+```tsp
+@service(#{ title: "Widget Service" })
+namespace DemoService;
+
+@route("/widgets")
+@tag("Widgets")
+interface Widgets {
+  @test
+  @get
+  read(
+    @query isActive?: boolean,
+    @query count?: int32,
+    @query filter?: string,
+    @header ifMatch?: string,
+  ): void;
+}
+```
+
+## TypeScript
+
+### Request
+
+```ts src/api/widgetsClient/widgetsClientOperations.ts function read
+export async function read(client: WidgetsClientContext, options?: ReadOptions): Promise<void> {
+  const path = parse("/widgets{?isActive,count,filter}").expand({
+    ...(options?.isActive != undefined && { isActive: options.isActive }),
+    ...(options?.count != undefined && { count: options.count }),
+    ...(options?.filter != undefined && { filter: options.filter }),
+  });
+  const httpRequestOptions = {
+    headers: {
+      ...(options?.ifMatch != undefined && { "if-match": options.ifMatch }),
+    },
+  };
+  const response = await client.pathUnchecked(path).get(httpRequestOptions);
+
+  if (typeof options?.operationOptions?.onResponse === "function") {
+    options?.operationOptions?.onResponse(response);
+  }
+  if (+response.status === 204 && !response.body) {
+    return;
+  }
+  throw createRestError(response);
+}
+```
diff --git a/packages/http-client-js/test/scenarios/http-operations/paging.md b/packages/http-client-js/test/scenarios/http-operations/paging.md
index 4d763b04685..374b659a0a9 100644
--- a/packages/http-client-js/test/scenarios/http-operations/paging.md
+++ b/packages/http-client-js/test/scenarios/http-operations/paging.md
@@ -53,7 +53,7 @@ export function link(
 async function linkSend(client: TestClientContext, filter: string, options?: Record<string, any>) {
   const path = parse("/link{?filter,nextToken}").expand({
     filter: filter,
-    ...(options?.nextToken && { nextToken: options.nextToken }),
+    ...(options?.nextToken != undefined && { nextToken: options.nextToken }),
   });
   const httpRequestOptions = {
     headers: {},
@@ -174,7 +174,9 @@ export function link(
 async function linkSend(client: TestClientContext, filter: string, options?: Record<string, any>) {
   const path = parse("/link{?filter,maxPageSize}").expand({
     filter: filter,
-    ...(options?.maxPageSize && { maxPageSize: options.maxPageSize }),
+    ...(options?.maxPageSize != undefined && {
+      maxPageSize: options.maxPageSize,
+    }),
   });
   const httpRequestOptions = {
     headers: {},
diff --git a/packages/http-client-js/test/scenarios/http-operations/query-parameter.md b/packages/http-client-js/test/scenarios/http-operations/query-parameter.md
index c29d575ff08..9cd81aadb04 100644
--- a/packages/http-client-js/test/scenarios/http-operations/query-parameter.md
+++ b/packages/http-client-js/test/scenarios/http-operations/query-parameter.md
@@ -24,7 +24,7 @@ export async function headModel(
   const path = parse("/").expand({});
   const httpRequestOptions = {
     headers: {
-      ...(input.foo && { foo: input.foo }),
+      ...(input.foo != undefined && { foo: input.foo }),
     },
     body: jsonVisibilityModelToTransportTransform(input),
   };
diff --git a/packages/http-client-js/test/scenarios/operation-parameters/body_root_anonymous.md b/packages/http-client-js/test/scenarios/operation-parameters/body_root_anonymous.md
index a33507c5ff6..20a306a324d 100644
--- a/packages/http-client-js/test/scenarios/operation-parameters/body_root_anonymous.md
+++ b/packages/http-client-js/test/scenarios/operation-parameters/body_root_anonymous.md
@@ -32,7 +32,7 @@ export async function create(
   const path = parse("/").expand({});
   const httpRequestOptions = {
     headers: {
-      ...(widget.foo && { foo: widget.foo }),
+      ...(widget.foo != undefined && { foo: widget.foo }),
     },
     body: {
       id: widget.id,
diff --git a/packages/http-client-js/test/scenarios/operation-parameters/with_body_property.md b/packages/http-client-js/test/scenarios/operation-parameters/with_body_property.md
index ff0787efd73..1434a52e982 100644
--- a/packages/http-client-js/test/scenarios/operation-parameters/with_body_property.md
+++ b/packages/http-client-js/test/scenarios/operation-parameters/with_body_property.md
@@ -26,7 +26,7 @@ export async function create(
   const path = parse("/").expand({});
   const httpRequestOptions = {
     headers: {
-      ...(options?.foo && { foo: options.foo }),
+      ...(options?.foo != undefined && { foo: options.foo }),
     },
     body: jsonWidgetToTransportTransform(widget),
   };
diff --git a/packages/http-client-js/test/scenarios/operation-parameters/with_body_root.md b/packages/http-client-js/test/scenarios/operation-parameters/with_body_root.md
index a9f651a40cf..a2a6604ec89 100644
--- a/packages/http-client-js/test/scenarios/operation-parameters/with_body_root.md
+++ b/packages/http-client-js/test/scenarios/operation-parameters/with_body_root.md
@@ -27,7 +27,7 @@ export async function create(
   const path = parse("/").expand({});
   const httpRequestOptions = {
     headers: {
-      ...(widget.foo && { foo: widget.foo }),
+      ...(widget.foo != undefined && { foo: widget.foo }),
     },
     body: jsonWidgetToTransportTransform(widget),
   };