diff --git a/usr.bin/sdiff/sdiff.1 b/usr.bin/sdiff/sdiff.1
--- a/usr.bin/sdiff/sdiff.1
+++ b/usr.bin/sdiff/sdiff.1
@@ -3,7 +3,7 @@
 .\" Written by Raymond Lai <ray@cyth.net>.
 .\" Public domain.
 .\"
-.Dd April 8, 2017
+.Dd February 16, 2024
 .Dt SDIFF 1
 .Os
 .Sh NAME
@@ -117,8 +117,6 @@
 Ignore blank lines.
 .It Fl E -ignore-tab-expansion
 Treat tabs and eight spaces as the same.
-.It Fl t -ignore-tabs
-Ignore tabs.
 .It Fl H -speed-large-files
 Assume scattered small changes in a large file.
 .It Fl -ignore-file-name-case
diff --git a/usr.bin/sdiff/sdiff.c b/usr.bin/sdiff/sdiff.c
--- a/usr.bin/sdiff/sdiff.c
+++ b/usr.bin/sdiff/sdiff.c
@@ -18,6 +18,7 @@
 #include <getopt.h>
 #include <limits.h>
 #include <paths.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -68,9 +69,10 @@
 static size_t line_width;	/* width of a line (two columns and divider) */
 static size_t width;		/* width of each column */
 static size_t file1ln, file2ln;	/* line number of file1 and file2 */
-static int Iflag = 0;	/* ignore sets matching regexp */
-static int	lflag;		/* print only left column for identical lines */
-static int	sflag;		/* skip identical lines */
+static bool	Iflag;		/* ignore sets matching regexp */
+static bool	lflag;		/* print only left column for identical lines */
+static bool	sflag;		/* skip identical lines */
+static bool	tflag;		/* expand tabs */
 FILE *outfp;		/* file to save changes to */
 const char *tmpdir;	/* TMPDIR or /tmp */
 
@@ -126,7 +128,7 @@
 	"\t-d, --minimal: minimize diff size.",
 	"\t-I RE, --ignore-matching-lines=RE: ignore changes whose line matches RE.",
 	"\t-i, --ignore-case: do a case-insensitive comparison.",
-	"\t-t, --expand-tabs: sxpand tabs to spaces.",
+	"\t-t, --expand-tabs: expand tabs to spaces.",
 	"\t-W, --ignore-all-spaces: ignore all spaces.",
 	"\t--speed-large-files: assume large file with scattered changes.",
 	"\t--strip-trailing-cr: strip trailing carriage return.",
@@ -256,7 +258,6 @@
 		case 'd':
 		case 'E':
 		case 'i':
-		case 't':
 		case 'W':
 			diffargv[1]  = realloc(diffargv[1], sizeof(char) * strlen(diffargv[1]) + 2);
 			/*
@@ -274,18 +275,21 @@
 			diffargv[0] = diffprog = optarg;
 			break;
 		case 'I':
-			Iflag = 1;
+			Iflag = true;
 			diffargv[diffargc++] = I_arg;
 			diffargv[diffargc++] = optarg;
 			break;
 		case 'l':
-			lflag = 1;
+			lflag = true;
 			break;
 		case 'o':
 			outfile = optarg;
 			break;
 		case 's':
-			sflag = 1;
+			sflag = true;
+			break;
+		case 't':
+			tflag = true;
 			break;
 		case 'w':
 			wflag = strtonum(optarg, WIDTH_MIN,
@@ -525,12 +529,19 @@
 			 */
 			if (new_col > col_max)
 				return;
-			*col = new_col;
+			if (tflag) {
+				do {
+					putchar(' ');
+				} while (++*col < new_col);
+			} else {
+				putchar(*s);
+				*col = new_col;
+			}
 			break;
 		default:
-			++(*col);
+			++*col;
+			putchar(*s);
 		}
-		putchar(*s);
 	}
 }
 
diff --git a/usr.bin/sdiff/tests/sdiff_test.sh b/usr.bin/sdiff/tests/sdiff_test.sh
--- a/usr.bin/sdiff/tests/sdiff_test.sh
+++ b/usr.bin/sdiff/tests/sdiff_test.sh
@@ -191,6 +191,21 @@
 $(atf_get_srcdir)/d_input2 >/dev/null ; cat merge.out"
 }
 
+atf_test_case tflag
+tflag_head()
+{
+	atf_set "descr" "Checks tab expansion"
+}
+tflag_body()
+{
+	printf "a\tb\n" >a
+	printf "b\ta\n" >b
+	atf_check -s exit:1 -o match:"a	b" \
+		  sdiff a b
+	atf_check -s exit:1 -o match:"a       b" \
+		  sdiff -t a b
+}
+
 atf_init_test_cases()
 {
 	atf_add_test_case flags
@@ -203,4 +218,5 @@
 	atf_add_test_case dot
 	atf_add_test_case stdin
 	atf_add_test_case short
+	atf_add_test_case tflag
 }