diff --git a/src/conditional_operator.rs b/src/conditional_operator.rs
index bb297c22ab..d3fe826b9f 100644
--- a/src/conditional_operator.rs
+++ b/src/conditional_operator.rs
@@ -9,6 +9,8 @@ pub(crate) enum ConditionalOperator {
   Inequality,
   /// `=~`
   RegexMatch,
+  /// `!~`
+  RegexNotMatch,
 }
 
 impl Display for ConditionalOperator {
@@ -17,6 +19,7 @@ impl Display for ConditionalOperator {
       Self::Equality => write!(f, "=="),
       Self::Inequality => write!(f, "!="),
       Self::RegexMatch => write!(f, "=~"),
+      Self::RegexNotMatch => write!(f, "!~"),
     }
   }
 }
diff --git a/src/evaluator.rs b/src/evaluator.rs
index b83c8cf70c..c69ea1fc78 100644
--- a/src/evaluator.rs
+++ b/src/evaluator.rs
@@ -245,6 +245,9 @@ impl<'src, 'run> Evaluator<'src, 'run> {
       ConditionalOperator::RegexMatch => Regex::new(&rhs_value)
         .map_err(|source| Error::RegexCompile { source })?
         .is_match(&lhs_value),
+      ConditionalOperator::RegexNotMatch => !Regex::new(&rhs_value)
+        .map_err(|source| Error::RegexCompile { source })?
+        .is_match(&lhs_value),
     };
     Ok(condition)
   }
diff --git a/src/lexer.rs b/src/lexer.rs
index 2c56db9dcf..eaa4417535 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -475,7 +475,7 @@ impl<'src> Lexer<'src> {
     match start {
       ' ' | '\t' => self.lex_whitespace(),
       '!' if self.rest().starts_with("!include") => Err(self.error(Include)),
-      '!' => self.lex_digraph('!', '=', BangEquals),
+      '!' => self.lex_choices('!', &[('=', BangEquals), ('~', BangTilde)], Unspecified),
       '#' => self.lex_comment(),
       '$' => self.lex_single(Dollar),
       '&' => self.lex_digraph('&', '&', AmpersandAmpersand),
@@ -949,6 +949,7 @@ mod tests {
       Asterisk => "*",
       At => "@",
       BangEquals => "!=",
+      BangTilde => "!~",
       BarBar => "||",
       BraceL => "{",
       BraceR => "}",
diff --git a/src/parser.rs b/src/parser.rs
index 32a5575159..adfe8fbd9e 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -614,6 +614,8 @@ impl<'run, 'src> Parser<'run, 'src> {
       ConditionalOperator::Inequality
     } else if self.accepted(EqualsTilde)? {
       ConditionalOperator::RegexMatch
+    } else if self.accepted(BangTilde)? {
+      ConditionalOperator::RegexNotMatch
     } else {
       self.expect(EqualsEquals)?;
       ConditionalOperator::Equality
diff --git a/src/summary.rs b/src/summary.rs
index 76483d63ec..bab3d5fd5e 100644
--- a/src/summary.rs
+++ b/src/summary.rs
@@ -360,6 +360,7 @@ pub enum ConditionalOperator {
   Equality,
   Inequality,
   RegexMatch,
+  RegexNotMatch,
 }
 
 impl ConditionalOperator {
@@ -368,6 +369,7 @@ impl ConditionalOperator {
       full::ConditionalOperator::Equality => Self::Equality,
       full::ConditionalOperator::Inequality => Self::Inequality,
       full::ConditionalOperator::RegexMatch => Self::RegexMatch,
+      full::ConditionalOperator::RegexNotMatch => Self::RegexNotMatch,
     }
   }
 }
diff --git a/src/token_kind.rs b/src/token_kind.rs
index 850afa9629..be8af19f5f 100644
--- a/src/token_kind.rs
+++ b/src/token_kind.rs
@@ -7,6 +7,7 @@ pub(crate) enum TokenKind {
   At,
   Backtick,
   BangEquals,
+  BangTilde,
   BarBar,
   BraceL,
   BraceR,
@@ -51,6 +52,7 @@ impl Display for TokenKind {
         At => "'@'",
         Backtick => "backtick",
         BangEquals => "'!='",
+        BangTilde => "'!~'",
         BarBar => "'||'",
         BraceL => "'{'",
         BraceR => "'}'",
diff --git a/tests/conditional.rs b/tests/conditional.rs
index 4eab2f4d72..8eae1351d6 100644
--- a/tests/conditional.rs
+++ b/tests/conditional.rs
@@ -136,7 +136,7 @@ test! {
   ",
   stdout: "",
   stderr: "
-    error: Expected '&&', '!=', '||', '==', '=~', '+', or '/', but found identifier
+    error: Expected '&&', '!=', '!~', '||', '==', '=~', '+', or '/', but found identifier
      ——▶ justfile:1:12
       │
     1 │ a := if '' a '' { '' } else { b }
diff --git a/tests/regexes.rs b/tests/regexes.rs
index 7a53a0af5c..3b13a72578 100644
--- a/tests/regexes.rs
+++ b/tests/regexes.rs
@@ -64,3 +64,23 @@ fn bad_regex_fails_at_runtime() {
     .status(EXIT_FAILURE)
     .run();
 }
+
+#[test]
+fn not_matching_regex() {
+  Test::new()
+    .justfile(
+      "
+      foo := if 'Foo' !~ '^ab+c' {
+        'no'
+      } else {
+        'yes'
+      }
+
+      default:
+        echo {{ foo }}
+    ",
+    )
+    .stderr("echo no\n")
+    .stdout("no\n")
+    .run();
+}