diff --git a/usr.bin/diff/diff.1 b/usr.bin/diff/diff.1
--- a/usr.bin/diff/diff.1
+++ b/usr.bin/diff/diff.1
@@ -27,7 +27,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd June 29, 2024
+.Dd July 26, 2024
 .Dt DIFF 1
 .Os
 .Sh NAME
@@ -202,7 +202,7 @@
 .Op Fl aBbditwW
 .Op Fl -color Ns = Ns Ar when
 .Op Fl -expand-tabs
-.Op Fl -ignore-all-blanks
+.Op Fl -ignore-all-space
 .Op Fl -ignore-blank-lines
 .Op Fl -ignore-case
 .Op Fl -minimal
@@ -469,7 +469,7 @@
 the indentation of the original source lines and make the output listing
 difficult to interpret.
 This option will preserve the original source's indentation.
-.It Fl w -ignore-all-blanks
+.It Fl w -ignore-all-space
 Is similar to
 .Fl b -ignore-space-change
 but causes whitespace (blanks and tabs) to be totally ignored.
diff --git a/usr.bin/diff/diff.c b/usr.bin/diff/diff.c
--- a/usr.bin/diff/diff.c
+++ b/usr.bin/diff/diff.c
@@ -629,7 +629,7 @@
 	    "       diff [-aBbdilNPprsTtw] [-c | -e | -f | -n | -q | -u] [--ignore-case]\n"
 	    "            [--no-ignore-case] [--normal] [--tabsize] [-I pattern] [-L label]\n"
 	    "            [-F pattern] [-S name] [-X file] [-x pattern] dir1 dir2\n"
-	    "       diff [-aBbditwW] [--expand-tabs] [--ignore-all-blanks]\n"
+	    "       diff [-aBbditwW] [--expand-tabs] [--ignore-all-space]\n"
 	    "            [--ignore-blank-lines] [--ignore-case] [--minimal]\n"
 	    "            [--no-ignore-file-name-case] [--strip-trailing-cr]\n"
 	    "            [--suppress-common-lines] [--tabsize] [--text] [--width]\n"