diff --git a/src/pages-and-resources/teams/Settings.jsx b/src/pages-and-resources/teams/Settings.jsx
index ee765378f..31dc644cd 100644
--- a/src/pages-and-resources/teams/Settings.jsx
+++ b/src/pages-and-resources/teams/Settings.jsx
@@ -61,7 +61,7 @@ function TeamSettings({
       validationSchema={{
         maxTeamSize: Yup.number()
           .required(intl.formatMessage(messages.maxTeamSizeEmpty))
-          .min(TeamSizes.MIN)
+          .min(TeamSizes.MIN, intl.formatMessage(messages.maxTeamSizeInvalid))
           .max(
             TeamSizes.MAX,
             intl.formatMessage(messages.maxTeamSizeTooHigh, {
@@ -79,8 +79,8 @@ function TeamSettings({
               .required(intl.formatMessage(messages.teamSetFormDescriptionError))
               .trim(),
             maxTeamSize: Yup.number()
-              .required(intl.formatMessage(messages.maxTeamSizeEmpty))
-              .min(TeamSizes.MIN)
+              .nullable()
+              .min(TeamSizes.MIN, intl.formatMessage(messages.maxTeamSizeInvalid))
               .max(
                 TeamSizes.MAX,
                 intl.formatMessage(messages.maxTeamSizeTooHigh, {
diff --git a/src/pages-and-resources/teams/messages.js b/src/pages-and-resources/teams/messages.js
index b6b8aedd5..078385109 100644
--- a/src/pages-and-resources/teams/messages.js
+++ b/src/pages-and-resources/teams/messages.js
@@ -30,9 +30,13 @@ const messages = defineMessages({
     defaultMessage: 'The maximum number of learners that can join a team',
   },
   maxTeamSizeEmpty: {
-    id: 'authoring.pagesAndResources.teams.teamSize.maxTeamSizeInvalid',
+    id: 'authoring.pagesAndResources.teams.teamSize.maxTeamSizeEmpty',
     defaultMessage: 'Enter max team size',
   },
+  maxTeamSizeInvalid: {
+    id: 'authoring.pagesAndResources.teams.teamSize.maxTeamSizeInvalid',
+    defaultMessage: 'Max team size must be a positive number larger than zero.',
+  },
   maxTeamSizeTooHigh: {
     id: 'authoring.pagesAndResources.teams.teamSize.maxTeamSizeTooHigh',
     defaultMessage: 'Max team size must less than {max}',