diff --git a/2nd-gen/packages/core/components/infield-button/InfieldButton.base.ts b/2nd-gen/packages/core/components/infield-button/InfieldButton.base.ts
new file mode 100644
index 00000000000..c2d8bd464ba
--- /dev/null
+++ b/2nd-gen/packages/core/components/infield-button/InfieldButton.base.ts
@@ -0,0 +1,63 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { property } from 'lit/decorators.js';
+
+import { ButtonBase } from '@spectrum-web-components/core/components/button';
+import { SpectrumElement } from '@spectrum-web-components/core/element/index.js';
+
+import {
+  INFIELD_BUTTON_VALID_SIZES,
+  type InfieldButtonSize,
+} from './InfieldButton.types.js';
+
+/**
+ * Abstract base class for infield button components. Extends ButtonBase with a
+ * restricted size set, quiet treatment, and non-focusable shadow root.
+ *
+ * Infield buttons are always embedded inside a form field (e.g. number field). They are
+ * clickable via pointer only; they are not in the tab order and not independently focusable.
+ * All keyboard behavior is owned by the parent field, which also provides the visible
+ * focus ring. The parent field is expected to set the `size` attribute.
+ *
+ * @slot icon - Icon to display inside the button.
+ *
+ * @attribute {ElementSize} size - Size delegated from the parent field. Defaults to
+ *   medium when no parent sets it, though standalone usage is not supported.
+ */
+export abstract class InfieldButtonBase extends ButtonBase {
+  // ────────────────────
+  //     API OVERRIDES
+  // ────────────────────
+
+  /** @internal */
+  static override readonly VALID_SIZES: readonly InfieldButtonSize[] =
+    INFIELD_BUTTON_VALID_SIZES;
+
+  // Infield buttons are clickable but never independently focusable. The parent field
+  // owns keyboard behavior and supplies the only focus ring.
+  static override shadowRootOptions: ShadowRootInit = {
+    ...SpectrumElement.shadowRootOptions,
+    delegatesFocus: false,
+  };
+
+  // ───────────────────
+  //     API ADDITIONS
+  // ───────────────────
+
+  /**
+   * Applies the quiet (no-border) visual treatment. Used when the infield button
+   * is part of a quiet field variant.
+   */
+  @property({ type: Boolean, reflect: true })
+  public quiet: boolean = false;
+}
diff --git a/2nd-gen/packages/core/components/infield-button/InfieldButton.types.ts b/2nd-gen/packages/core/components/infield-button/InfieldButton.types.ts
new file mode 100644
index 00000000000..4f5acdf844b
--- /dev/null
+++ b/2nd-gen/packages/core/components/infield-button/InfieldButton.types.ts
@@ -0,0 +1,30 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import type { ElementSize } from '@spectrum-web-components/core/mixins/index.js';
+
+// ──────────────────
+//     SHARED
+// ──────────────────
+
+export const INFIELD_BUTTON_VALID_SIZES = [
+  's',
+  'm',
+  'l',
+  'xl',
+] as const satisfies readonly ElementSize[];
+
+// ──────────────────
+//     TYPES
+// ──────────────────
+
+export type InfieldButtonSize = (typeof INFIELD_BUTTON_VALID_SIZES)[number];
diff --git a/2nd-gen/packages/core/components/infield-button/index.ts b/2nd-gen/packages/core/components/infield-button/index.ts
new file mode 100644
index 00000000000..be350e0d02a
--- /dev/null
+++ b/2nd-gen/packages/core/components/infield-button/index.ts
@@ -0,0 +1,13 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+export * from './InfieldButton.base.js';
+export * from './InfieldButton.types.js';
diff --git a/2nd-gen/packages/core/package.json b/2nd-gen/packages/core/package.json
index 2b51e3bf58c..ddac4caed7e 100644
--- a/2nd-gen/packages/core/package.json
+++ b/2nd-gen/packages/core/package.json
@@ -51,6 +51,14 @@
       "types": "./dist/components/button/index.d.ts",
       "import": "./dist/components/button/index.js"
     },
+    "./components/infield-button": {
+      "types": "./dist/components/infield-button/index.d.ts",
+      "import": "./dist/components/infield-button/index.js"
+    },
+    "./components/infield-button/index.js": {
+      "types": "./dist/components/infield-button/index.d.ts",
+      "import": "./dist/components/infield-button/index.js"
+    },
     "./components/button-group": {
       "types": "./dist/components/button-group/index.d.ts",
       "import": "./dist/components/button-group/index.js"
@@ -236,6 +244,12 @@
       "components/button": [
         "dist/components/button/index.d.ts"
       ],
+      "components/infield-button": [
+        "dist/components/infield-button/index.d.ts"
+      ],
+      "components/infield-button/index.js": [
+        "dist/components/infield-button/index.d.ts"
+      ],
       "components/button-group": [
         "dist/components/button-group/index.d.ts"
       ],
diff --git a/2nd-gen/packages/swc/components/infield-button/InfieldButton.ts b/2nd-gen/packages/swc/components/infield-button/InfieldButton.ts
new file mode 100644
index 00000000000..0c10618206d
--- /dev/null
+++ b/2nd-gen/packages/swc/components/infield-button/InfieldButton.ts
@@ -0,0 +1,71 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+import { CSSResultArray, html, TemplateResult } from 'lit';
+import { classMap } from 'lit/directives/class-map.js';
+import { ifDefined } from 'lit/directives/if-defined.js';
+
+import {
+  INFIELD_BUTTON_VALID_SIZES,
+  InfieldButtonBase,
+  type InfieldButtonSize,
+} from '@spectrum-web-components/core/components/infield-button';
+
+import styles from './infield-button.css';
+
+/**
+ * A compact icon button embedded inside a form field (e.g. number field increment/decrement
+ * control, search field clear button). Clickable via pointer only; not in the tab order.
+ * The parent field owns all keyboard behavior and provides the visible focus ring.
+ *
+ * @element swc-infield-button
+ * @since 2.0.0
+ *
+ * @slot icon - Icon to display inside the button.
+ *
+ * @example
+ * <swc-infield-button accessible-label="Increment value" size="m">
+ *   <sp-icon-chevron100 slot="icon"></sp-icon-chevron100>
+ * </swc-infield-button>
+ */
+export class InfieldButton extends InfieldButtonBase {
+  // ────────────────────
+  //     API OVERRIDES
+  // ────────────────────
+
+  /** @internal */
+  static override readonly VALID_SIZES: readonly InfieldButtonSize[] =
+    INFIELD_BUTTON_VALID_SIZES;
+
+  // ──────────────────────────────
+  //     RENDERING & STYLING
+  // ──────────────────────────────
+
+  public static override get styles(): CSSResultArray {
+    return [styles];
+  }
+
+  protected override render(): TemplateResult {
+    return html`
+      <button
+        class=${classMap({ 'swc-InfieldButton': true })}
+        type="button"
+        tabindex="-1"
+        @click=${this.handleClick}
+        ?disabled=${this.disabled}
+        aria-label=${ifDefined(this.accessibleLabel)}
+      >
+        <slot name="icon"></slot>
+      </button>
+    `;
+  }
+}
diff --git a/2nd-gen/packages/swc/components/infield-button/index.ts b/2nd-gen/packages/swc/components/infield-button/index.ts
new file mode 100644
index 00000000000..d0c1a91ab09
--- /dev/null
+++ b/2nd-gen/packages/swc/components/infield-button/index.ts
@@ -0,0 +1,12 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+export * from './InfieldButton.js';
diff --git a/2nd-gen/packages/swc/components/infield-button/infield-button.css b/2nd-gen/packages/swc/components/infield-button/infield-button.css
new file mode 100644
index 00000000000..ac2b1612f1a
--- /dev/null
+++ b/2nd-gen/packages/swc/components/infield-button/infield-button.css
@@ -0,0 +1,16 @@
+/*
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+
+/* Placeholder — full styles authored in Phase 5 */
+:host {
+  display: inline-flex;
+}
diff --git a/2nd-gen/packages/swc/components/infield-button/swc-infield-button.ts b/2nd-gen/packages/swc/components/infield-button/swc-infield-button.ts
new file mode 100644
index 00000000000..e53632c52ab
--- /dev/null
+++ b/2nd-gen/packages/swc/components/infield-button/swc-infield-button.ts
@@ -0,0 +1,22 @@
+/**
+ * Copyright 2026 Adobe. All rights reserved.
+ * This file is licensed to you under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License. You may obtain a copy
+ * of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under
+ * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
+ * OF ANY KIND, either express or implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+import { defineElement } from '@spectrum-web-components/core/element/index.js';
+
+import { InfieldButton } from './InfieldButton.js';
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'swc-infield-button': InfieldButton;
+  }
+}
+
+defineElement('swc-infield-button', InfieldButton);