diff --git a/changelog_unreleased/flow/11398.md b/changelog_unreleased/flow/11398.md
new file mode 100644
index 000000000..02b564d6f
--- /dev/null
+++ b/changelog_unreleased/flow/11398.md
@@ -0,0 +1,26 @@
+#### Print leading semi before Flow variance sigils (#11398 by @noppa)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+class A {
+  +one = function() {};
+  -two = val();
+  +#privOne = val();
+  static +#privTwo = val();
+}
+// Prettier stable
+class A {
+  +one = function() {}
+  -two = val()
+  +#privOne = val()
+  static +#privTwo = val()
+}
+// Prettier main
+class A {
+  +one = function() {};
+  -two = val();
+  +#privOne = val()
+  static +#privTwo = val()
+}
+```
diff --git a/src/language-js/print/statement.js b/src/language-js/print/statement.js
index 9dc33a742..c7573faf7 100644
--- a/src/language-js/print/statement.js
+++ b/src/language-js/print/statement.js
@@ -201,6 +201,17 @@ function shouldPrintSemicolonAfterClassProperty(node, nextNode) {
     }
   }
 
+  // Flow variance sigil +/- requires semi if there's no
+  // "declare" or "static" keyword before it.
+  if (
+    isClassProperty(nextNode) &&
+    nextNode.variance &&
+    !nextNode.static &&
+    !nextNode.declare
+  ) {
+    return true;
+  }
+
   switch (nextNode.type) {
     case "ClassProperty":
     case "PropertyDefinition":
diff --git a/tests/format/flow/no-semi/__snapshots__/jsfmt.spec.js.snap b/tests/format/flow/no-semi/__snapshots__/jsfmt.spec.js.snap
index 2a25e9c70..36cf0be3c 100644
--- a/tests/format/flow/no-semi/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/format/flow/no-semi/__snapshots__/jsfmt.spec.js.snap
@@ -2,7 +2,7 @@
 
 exports[`comments.js - {"semi":false} format 1`] = `
 ====================================options=====================================
-parsers: ["flow", "babel"]
+parsers: ["flow", "babel", "babel-flow"]
 printWidth: 80
 semi: false
                                                                                 | printWidth
@@ -37,7 +37,7 @@ x
 
 exports[`comments.js format 1`] = `
 ====================================options=====================================
-parsers: ["flow", "babel"]
+parsers: ["flow", "babel", "babel-flow"]
 printWidth: 80
                                                                                 | printWidth
 =====================================input======================================
@@ -69,9 +69,66 @@ x;
 ================================================================================
 `;
 
+exports[`flow-class-properties.js - {"semi":false} format 1`] = `
+====================================options=====================================
+parsers: ["flow", "babel", "babel-flow"]
+printWidth: 80
+semi: false
+                                                                                | printWidth
+=====================================input======================================
+class A {
+  +one = function() {};
+  -two = val();
+  static +three = val();
+  +#privOne = val();
+  static +#privTwo = val();
+  +[computed] = val();
+}
+
+=====================================output=====================================
+class A {
+  +one = function () {};
+  -two = val()
+  static +three = val();
+  +#privOne = val()
+  static +#privTwo = val();
+  +[computed] = val()
+}
+
+================================================================================
+`;
+
+exports[`flow-class-properties.js format 1`] = `
+====================================options=====================================
+parsers: ["flow", "babel", "babel-flow"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+class A {
+  +one = function() {};
+  -two = val();
+  static +three = val();
+  +#privOne = val();
+  static +#privTwo = val();
+  +[computed] = val();
+}
+
+=====================================output=====================================
+class A {
+  +one = function () {};
+  -two = val();
+  static +three = val();
+  +#privOne = val();
+  static +#privTwo = val();
+  +[computed] = val();
+}
+
+================================================================================
+`;
+
 exports[`flow-interfaces.js - {"semi":false} format 1`] = `
 ====================================options=====================================
-parsers: ["flow", "babel"]
+parsers: ["flow", "babel", "babel-flow"]
 printWidth: 80
 semi: false
                                                                                 | printWidth
@@ -157,7 +214,7 @@ interface E {
 
 exports[`flow-interfaces.js format 1`] = `
 ====================================options=====================================
-parsers: ["flow", "babel"]
+parsers: ["flow", "babel", "babel-flow"]
 printWidth: 80
                                                                                 | printWidth
 =====================================input======================================
@@ -242,7 +299,7 @@ interface E {
 
 exports[`no-semi.js - {"semi":false} format 1`] = `
 ====================================options=====================================
-parsers: ["flow", "babel"]
+parsers: ["flow", "babel", "babel-flow"]
 printWidth: 80
 semi: false
                                                                                 | printWidth
@@ -263,7 +320,7 @@ semi: false
 
 exports[`no-semi.js format 1`] = `
 ====================================options=====================================
-parsers: ["flow", "babel"]
+parsers: ["flow", "babel", "babel-flow"]
 printWidth: 80
                                                                                 | printWidth
 =====================================input======================================
diff --git a/tests/format/flow/no-semi/flow-class-properties.js b/tests/format/flow/no-semi/flow-class-properties.js
new file mode 100644
index 000000000..e6cd0014e
--- /dev/null
+++ b/tests/format/flow/no-semi/flow-class-properties.js
@@ -0,0 +1,8 @@
+class A {
+  +one = function() {};
+  -two = val();
+  static +three = val();
+  +#privOne = val();
+  static +#privTwo = val();
+  +[computed] = val();
+}
diff --git a/tests/format/flow/no-semi/jsfmt.spec.js b/tests/format/flow/no-semi/jsfmt.spec.js
index 2f93d9870..b01ec0778 100644
--- a/tests/format/flow/no-semi/jsfmt.spec.js
+++ b/tests/format/flow/no-semi/jsfmt.spec.js
@@ -1,2 +1,2 @@
-run_spec(__dirname, ["flow", "babel"]);
-run_spec(__dirname, ["flow", "babel"], { semi: false });
+run_spec(__dirname, ["flow", "babel", "babel-flow"]);
+run_spec(__dirname, ["flow", "babel", "babel-flow"], { semi: false });