diff --git a/src/global_styling/mixins/_header.scss b/src/global_styling/mixins/_header.scss
deleted file mode 100644
index aae8c7eb1fc..00000000000
--- a/src/global_styling/mixins/_header.scss
+++ /dev/null
@@ -1,29 +0,0 @@
-@import '../variables/header';
-
-@mixin euiHeaderAffordForFixed($headerHeight: $euiHeaderHeightCompensation) {
-  @warn 'This mixin will shortly be deprecated. Use the CSS variable var(--euiFixedHeadersOffset) instead, which updates dynamically based on the number of fixed headers on the page.';
-
-  // The `@at-root #{&}` allows for grouping alongside another specific body class.
-  // When not applied inside of another selector, it simply renders with the single class
-  @at-root #{&}.euiBody--headerIsFixed {
-    padding-top: $headerHeight;
-
-    // When the EuiHeader is fixed, we need to account for it in the position of the flyout
-    &:not(.euiDataGrid__restrictBody) .euiFlyout,
-    .euiCollapsibleNav {
-      top: $headerHeight;
-      height: calc(100% - #{$headerHeight});
-    }
-
-    @include euiBreakpoint('m', 'l', 'xl') {
-      .euiPageSideBar--sticky {
-        max-height: calc(100vh - #{$headerHeight});
-        top: #{$headerHeight};
-      }
-    }
-
-    &:not(.euiDataGrid__restrictBody) .euiOverlayMask[data-relative-to-header='below'] {
-      top: #{$headerHeight};
-    }
-  }
-}
diff --git a/src/global_styling/mixins/_index.scss b/src/global_styling/mixins/_index.scss
index 1e23b8a2228..0d8915a49d4 100644
--- a/src/global_styling/mixins/_index.scss
+++ b/src/global_styling/mixins/_index.scss
@@ -8,7 +8,6 @@
 
 @import 'button';
 @import 'form';
-@import 'header';
 @import 'loading';
 @import 'link';
 @import 'panel';
diff --git a/src/global_styling/variables/_header.scss b/src/global_styling/variables/_header.scss
deleted file mode 100644
index df68553c62e..00000000000
--- a/src/global_styling/variables/_header.scss
+++ /dev/null
@@ -1,3 +0,0 @@
-$euiHeaderHeight: $euiSizeXXL + $euiSizeS !default;
-// Use the following variable in other components to afford for the fixed header
-$euiHeaderHeightCompensation: $euiHeaderHeight !default;
diff --git a/src/global_styling/variables/_index.scss b/src/global_styling/variables/_index.scss
index 80fbed518bb..6971a19d892 100644
--- a/src/global_styling/variables/_index.scss
+++ b/src/global_styling/variables/_index.scss
@@ -21,7 +21,6 @@
 
 @import 'buttons';
 @import 'form';
-@import 'header';
 @import 'page';
 @import 'panel';
 @import 'tool_tip';
diff --git a/src/themes/amsterdam/global_styling/mixins/_index.scss b/src/themes/amsterdam/global_styling/mixins/_index.scss
index 986c7aa2391..3d83a4cd823 100644
--- a/src/themes/amsterdam/global_styling/mixins/_index.scss
+++ b/src/themes/amsterdam/global_styling/mixins/_index.scss
@@ -10,7 +10,6 @@
 
 @import '../../../../global_styling/mixins/button';
 @import '../../../../global_styling/mixins/form';
-@import '../../../../global_styling/mixins/header';
 @import '../../../../global_styling/mixins/loading';
 @import 'link';
 @import '../../../../global_styling/mixins/panel';
diff --git a/upcoming_changelogs/7264.md b/upcoming_changelogs/7264.md
new file mode 100644
index 00000000000..0ebd8034aa1
--- /dev/null
+++ b/upcoming_changelogs/7264.md
@@ -0,0 +1,3 @@
+**Breaking changes**
+
+- Removed `euiHeaderAffordForFixed` Sass mixin, and  `$euiHeaderHeight` and `$euiHeaderHeightCompensation` Sass variables. Use the CSS variable `--var(euiFixedHeadersOffset, 0)` instead.