diff --git a/.changeset/sparkly-experts-wave.md b/.changeset/sparkly-experts-wave.md
new file mode 100644
index 000000000..7f76b1860
--- /dev/null
+++ b/.changeset/sparkly-experts-wave.md
@@ -0,0 +1,5 @@
+---
+'@ithaka/pharos': patch
+---
+
+fix(modal): make modal full width and height on mobile viewports
diff --git a/packages/pharos/src/components/modal/pharos-modal.scss b/packages/pharos/src/components/modal/pharos-modal.scss
index 434d50578..cb3622622 100644
--- a/packages/pharos/src/components/modal/pharos-modal.scss
+++ b/packages/pharos/src/components/modal/pharos-modal.scss
@@ -61,8 +61,9 @@
 
 @media only screen and (width <= 570px) {
   .modal__dialog {
-    max-height: 88vh;
-    width: 88vw;
+    width: 100%;
+    height: 100dvh;
+    max-height: 100dvh;
   }
 
   :host([open]) .modal__dialog {