diff --git a/src/material/sidenav/drawer.spec.ts b/src/material/sidenav/drawer.spec.ts
index d65226cf1194..8d6e83ecb5a4 100644
--- a/src/material/sidenav/drawer.spec.ts
+++ b/src/material/sidenav/drawer.spec.ts
@@ -518,7 +518,7 @@ describe('MatDrawer', () => {
       expect(document.activeElement).toBe(firstFocusableElement);
     }));
 
-    it('should not trap focus when opened in "side" mode', fakeAsync(() => {
+    it('should not auto-focus by default when opened in "side" mode', fakeAsync(() => {
       testComponent.mode = 'side';
       fixture.detectChanges();
       lastFocusableElement.focus();
@@ -530,6 +530,19 @@ describe('MatDrawer', () => {
       expect(document.activeElement).toBe(lastFocusableElement);
     }));
 
+    it('should auto-focus when opened in "side" mode when enabled explicitly', fakeAsync(() => {
+      drawer.autoFocus = true;
+      testComponent.mode = 'side';
+      fixture.detectChanges();
+      lastFocusableElement.focus();
+
+      drawer.open();
+      fixture.detectChanges();
+      tick();
+
+      expect(document.activeElement).toBe(firstFocusableElement);
+    }));
+
     it('should focus the drawer if there are no focusable elements', fakeAsync(() => {
       fixture.destroy();
 
@@ -545,7 +558,7 @@ describe('MatDrawer', () => {
     }));
 
     it('should be able to disable auto focus', fakeAsync(() => {
-      testComponent.autoFocus = false;
+      drawer.autoFocus = false;
       testComponent.mode = 'push';
       fixture.detectChanges();
       lastFocusableElement.focus();
@@ -981,7 +994,7 @@ class DrawerDynamicPosition {
   // to be focusable across all platforms.
   template: `
     <mat-drawer-container>
-      <mat-drawer position="start" [mode]="mode" [autoFocus]="autoFocus">
+      <mat-drawer position="start" [mode]="mode">
         <input type="text" class="input1"/>
       </mat-drawer>
       <input type="text" class="input2"/>
@@ -989,7 +1002,6 @@ class DrawerDynamicPosition {
 })
 class DrawerWithFocusableElements {
   mode: string = 'over';
-  autoFocus = true;
 }
 
 @Component({
diff --git a/src/material/sidenav/drawer.ts b/src/material/sidenav/drawer.ts
index b5f113d893c9..934483a101ab 100644
--- a/src/material/sidenav/drawer.ts
+++ b/src/material/sidenav/drawer.ts
@@ -173,11 +173,22 @@ export class MatDrawer implements AfterContentInit, AfterContentChecked, OnDestr
   set disableClose(value: boolean) { this._disableClose = coerceBooleanProperty(value); }
   private _disableClose: boolean = false;
 
-  /** Whether the drawer should focus the first focusable element automatically when opened. */
+  /**
+   * Whether the drawer should focus the first focusable element automatically when opened.
+   * Defaults to false in when `mode` is set to `side`, otherwise defaults to `true`. If explicitly
+   * enabled, focus will be moved into the sidenav in `side` mode as well.
+   */
   @Input()
-  get autoFocus(): boolean { return this._autoFocus; }
+  get autoFocus(): boolean {
+    const value = this._autoFocus;
+
+    // Note that usually we disable auto focusing in `side` mode, because we don't know how the
+    // sidenav is being used, but in some cases it still makes sense to do it. If the consumer
+    // explicitly enabled `autoFocus`, we take it as them always wanting to enable it.
+    return value == null ? this.mode !== 'side' : value;
+  }
   set autoFocus(value: boolean) { this._autoFocus = coerceBooleanProperty(value); }
-  private _autoFocus: boolean = true;
+  private _autoFocus: boolean | undefined;
 
   /**
    * Whether the drawer is opened. We overload this because we trigger an event when it
@@ -253,11 +264,6 @@ export class MatDrawer implements AfterContentInit, AfterContentChecked, OnDestr
    */
   readonly _modeChanged = new Subject<void>();
 
-  get _isFocusTrapEnabled(): boolean {
-    // The focus trap is only enabled when the drawer is open in any mode other than side.
-    return this.opened && this.mode !== 'side';
-  }
-
   constructor(private _elementRef: ElementRef<HTMLElement>,
               private _focusTrapFactory: FocusTrapFactory,
               private _focusMonitor: FocusMonitor,
@@ -276,9 +282,7 @@ export class MatDrawer implements AfterContentInit, AfterContentChecked, OnDestr
           this._elementFocusedBeforeDrawerWasOpened = this._doc.activeElement as HTMLElement;
         }
 
-        if (this._isFocusTrapEnabled && this._focusTrap) {
-          this._trapFocus();
-        }
+        this._takeFocus();
       } else {
         this._restoreFocus();
       }
@@ -316,9 +320,12 @@ export class MatDrawer implements AfterContentInit, AfterContentChecked, OnDestr
     });
   }
 
-  /** Traps focus inside the drawer. */
-  private _trapFocus() {
-    if (!this.autoFocus) {
+  /**
+   * Moves focus into the drawer. Note that this works even if
+   * the focus trap is disabled in `side` mode.
+   */
+  private _takeFocus() {
+    if (!this.autoFocus || !this._focusTrap) {
       return;
     }
 
@@ -428,7 +435,8 @@ export class MatDrawer implements AfterContentInit, AfterContentChecked, OnDestr
   /** Updates the enabled state of the focus trap. */
   private _updateFocusTrapState() {
     if (this._focusTrap) {
-      this._focusTrap.enabled = this._isFocusTrapEnabled;
+      // The focus trap is only enabled when the drawer is open in any mode other than side.
+      this._focusTrap.enabled = this.opened && this.mode !== 'side';
     }
   }
 
diff --git a/tools/public_api_guard/material/sidenav.d.ts b/tools/public_api_guard/material/sidenav.d.ts
index bb81a8907070..2b351345768c 100644
--- a/tools/public_api_guard/material/sidenav.d.ts
+++ b/tools/public_api_guard/material/sidenav.d.ts
@@ -8,7 +8,6 @@ export declare class MatDrawer implements AfterContentInit, AfterContentChecked,
     _animationState: 'open-instant' | 'open' | 'void';
     readonly _closedStream: Observable<void>;
     _container?: MatDrawerContainer | undefined;
-    readonly _isFocusTrapEnabled: boolean;
     readonly _modeChanged: Subject<void>;
     readonly _openedStream: Observable<void>;
     readonly _width: number;