diff --git a/codex-rs/tui/src/diff_render.rs b/codex-rs/tui/src/diff_render.rs
index 9df58fb7e66f..9972a3fa635d 100644
--- a/codex-rs/tui/src/diff_render.rs
+++ b/codex-rs/tui/src/diff_render.rs
@@ -48,8 +48,10 @@ use std::path::PathBuf;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use unicode_width::UnicodeWidthChar;
 
+/// Replacement for a tab character in rendered diff content.
+const TAB_REPLACEMENT: &str = "    ";
 /// Display width of a tab character in columns.
-const TAB_WIDTH: usize = 4;
+const TAB_WIDTH: usize = TAB_REPLACEMENT.len();
 
 // -- Diff background palette --------------------------------------------------
 //
@@ -989,7 +991,10 @@ fn wrap_styled_spans(spans: &[RtSpan<'static>], max_cols: usize) -> Vec<Vec<RtSp
                     break;
                 };
                 let ch_len = ch.len_utf8();
-                current_line.push(RtSpan::styled(remaining[..ch_len].to_string(), style));
+                current_line.push(RtSpan::styled(
+                    remaining[..ch_len].replace('\t', TAB_REPLACEMENT),
+                    style,
+                ));
                 // Use fallback width 1 (not 0) so this branch always advances
                 // even if `ch` has unknown/zero display width.
                 col = ch.width().unwrap_or(if ch == '\t' { TAB_WIDTH } else { 1 });
@@ -998,7 +1003,7 @@ fn wrap_styled_spans(spans: &[RtSpan<'static>], max_cols: usize) -> Vec<Vec<RtSp
             }
 
             let (chunk, rest) = remaining.split_at(byte_end);
-            current_line.push(RtSpan::styled(chunk.to_string(), style));
+            current_line.push(RtSpan::styled(chunk.replace('\t', TAB_REPLACEMENT), style));
             col += chars_col;
             remaining = rest;
 
@@ -1370,6 +1375,15 @@ mod tests {
                     .render_ref(f.area(), f.buffer_mut())
             })
             .expect("draw");
+        assert!(
+            terminal
+                .backend()
+                .buffer()
+                .content()
+                .iter()
+                .all(|cell| !cell.symbol().contains('\t')),
+            "diff buffer should not contain literal tabs"
+        );
         assert_snapshot!(name, terminal.backend());
     }
 
@@ -2351,12 +2365,15 @@ mod tests {
     fn wrap_styled_spans_tabs_have_visible_width() {
         // A tab should count as TAB_WIDTH columns, not zero.
         // With max_cols=8, a tab (4 cols) + "abcde" (5 cols) = 9 cols → must wrap.
-        let spans = vec![RtSpan::raw("\tabcde")];
+        let style = Style::default().fg(Color::Green);
+        let spans = vec![RtSpan::styled("\tabcde", style)];
         let result = wrap_styled_spans(&spans, /*max_cols*/ 8);
-        assert!(
-            result.len() >= 2,
-            "tab + 5 chars should exceed 8 cols and wrap, got {} line(s): {result:?}",
-            result.len()
+        assert_eq!(
+            result,
+            vec![
+                vec![RtSpan::styled("    abcd", style)],
+                vec![RtSpan::styled("e", style)],
+            ]
         );
     }
 
@@ -2373,7 +2390,7 @@ mod tests {
                     .collect::<String>()
             })
             .collect();
-        assert_eq!(line_text, vec!["abcd", "\t", "界"]);
+        assert_eq!(line_text, vec!["abcd", "    ", "界"]);
 
         let line_width = |line: &[RtSpan<'static>]| -> usize {
             line.iter()
diff --git a/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_120x40.snap b/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_120x40.snap
index 07985926c47f..8a46e716af73 100644
--- a/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_120x40.snap
+++ b/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_120x40.snap
@@ -4,9 +4,9 @@ expression: terminal.backend()
 ---
 "• Edited 6 files (+9 -9)                                                                                                "
 "  └ assets/banner.txt (+3 -0)                                                                                           "
-"    1 +HEADER	VALUE                                                                                                     "
-"    2 +rocket	🚀                                                                                                        " Hidden by multi-width symbols: [(15, " ")]
-"    3 +city	東京                                                                                                        " Hidden by multi-width symbols: [(13, " "), (15, " ")]
+"    1 +HEADER    VALUE                                                                                                  "
+"    2 +rocket    🚀                                                                                                     " Hidden by multi-width symbols: [(18, " ")]
+"    3 +city    東京                                                                                                     " Hidden by multi-width symbols: [(16, " "), (18, " ")]
 "                                                                                                                        "
 "  └ examples/new_sample.rs (+3 -0)                                                                                      "
 "    1 +pub fn greet(name: &str) {                                                                                       "
@@ -20,8 +20,8 @@ expression: terminal.backend()
 "                                                                                                                        "
 "  └ scripts/calc.txt → scripts/calc.py (+1 -1)                                                                          "
 "    1  def add(a, b):                                                                                                   "
-"    2 -	return a + b                                                                                                    "
-"    2 +	return a + b + 42                                                                                               "
+"    2 -    return a + b                                                                                                 "
+"    2 +    return a + b + 42                                                                                            "
 "    3                                                                                                                   "
 "    4  print(add(1, 2))                                                                                                 "
 "                                                                                                                        "
diff --git a/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_80x24.snap b/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_80x24.snap
index b3da476a2df6..f7ba17c1c2fa 100644
--- a/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_80x24.snap
+++ b/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_80x24.snap
@@ -4,9 +4,9 @@ expression: terminal.backend()
 ---
 "• Edited 6 files (+9 -9)                                                        "
 "  └ assets/banner.txt (+3 -0)                                                   "
-"    1 +HEADER	VALUE                                                             "
-"    2 +rocket	🚀                                                                " Hidden by multi-width symbols: [(15, " ")]
-"    3 +city	東京                                                                " Hidden by multi-width symbols: [(13, " "), (15, " ")]
+"    1 +HEADER    VALUE                                                          "
+"    2 +rocket    🚀                                                             " Hidden by multi-width symbols: [(18, " ")]
+"    3 +city    東京                                                             " Hidden by multi-width symbols: [(16, " "), (18, " ")]
 "                                                                                "
 "  └ examples/new_sample.rs (+3 -0)                                              "
 "    1 +pub fn greet(name: &str) {                                               "
@@ -20,8 +20,8 @@ expression: terminal.backend()
 "                                                                                "
 "  └ scripts/calc.txt → scripts/calc.py (+1 -1)                                  "
 "    1  def add(a, b):                                                           "
-"    2 -	return a + b                                                            "
-"    2 +	return a + b + 42                                                       "
+"    2 -    return a + b                                                         "
+"    2 +    return a + b + 42                                                    "
 "    3                                                                           "
 "    4  print(add(1, 2))                                                         "
 "                                                                                "
diff --git a/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_94x35.snap b/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_94x35.snap
index 9eaffa6c91b9..c30d789fe920 100644
--- a/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_94x35.snap
+++ b/codex-rs/tui/src/snapshots/codex_tui__diff_render__tests__diff_gallery_94x35.snap
@@ -4,9 +4,9 @@ expression: terminal.backend()
 ---
 "• Edited 6 files (+9 -9)                                                                      "
 "  └ assets/banner.txt (+3 -0)                                                                 "
-"    1 +HEADER	VALUE                                                                           "
-"    2 +rocket	🚀                                                                              " Hidden by multi-width symbols: [(15, " ")]
-"    3 +city	東京                                                                              " Hidden by multi-width symbols: [(13, " "), (15, " ")]
+"    1 +HEADER    VALUE                                                                        "
+"    2 +rocket    🚀                                                                           " Hidden by multi-width symbols: [(18, " ")]
+"    3 +city    東京                                                                           " Hidden by multi-width symbols: [(16, " "), (18, " ")]
 "                                                                                              "
 "  └ examples/new_sample.rs (+3 -0)                                                            "
 "    1 +pub fn greet(name: &str) {                                                             "
@@ -20,8 +20,8 @@ expression: terminal.backend()
 "                                                                                              "
 "  └ scripts/calc.txt → scripts/calc.py (+1 -1)                                                "
 "    1  def add(a, b):                                                                         "
-"    2 -	return a + b                                                                          "
-"    2 +	return a + b + 42                                                                     "
+"    2 -    return a + b                                                                       "
+"    2 +    return a + b + 42                                                                  "
 "    3                                                                                         "
 "    4  print(add(1, 2))                                                                       "
 "                                                                                              "