diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -603,6 +603,17 @@
             parser::ToUpperCaseLetters(
                 parser::OmpScheduleClause::EnumToString(kind)));
       }
+      if (const auto &chunkExpr{
+              std::get<std::optional<parser::ScalarIntExpr>>(x.t)}) {
+        if (const auto chunkValue{GetIntValue(chunkExpr)}) {
+          if (*chunkValue <= 0) {
+            context_.Say(GetContext().clauseSource,
+                "The chunk size of the schedule clause must be a"
+                " positive integer expression."_err_en_US,
+                ContextDirectiveAsFortran());
+          }
+        }
+      }
     }
 
     if (ScheduleModifierHasType(
diff --git a/flang/test/Semantics/omp-do-schedule.f90 b/flang/test/Semantics/omp-do-schedule.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/omp-do-schedule.f90
@@ -0,0 +1,13 @@
+! RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.7.1 Schedule Clause
+program omp_doSchedule
+  integer :: i,n
+  real ::  a(100), y(100), z(100)
+  !ERROR: The chunk size of the schedule clause must be a positive integer expression.
+  !$omp do schedule(static, -1)
+  do i=2,n+1
+    y(i) = z(i-1) + a(i)
+  end do
+  !$omp end do
+end program omp_doSchedule
diff --git a/flang/test/Semantics/omp-do-schedule02.f90 b/flang/test/Semantics/omp-do-schedule02.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/omp-do-schedule02.f90
@@ -0,0 +1,15 @@
+!RUN: %S/test_errors.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.7.1 Schedule Clause
+program omp_doSchedule
+  integer :: i,n
+  real ::  a(100), y(100), z(100)
+  integer,parameter :: b = 10
+  integer,parameter :: c = 11
+  !ERROR: The chunk size of the schedule clause must be a positive integer expression.
+  !$omp do schedule(static,b-c)
+  do i=2,n+1
+    y(i) = z(i-1) + a(i)
+  end do
+  !$omp end do
+end program omp_doSchedule
diff --git a/flang/test/Semantics/omp-do-schedule03.f90 b/flang/test/Semantics/omp-do-schedule03.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/omp-do-schedule03.f90
@@ -0,0 +1,28 @@
+! RUN: %S/test_symbols.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.7.1 Schedule Clause
+! Test that does not catch non constant integer expressions like xx - xx.
+  !DEF: /ompdoschedule MainProgram
+ program ompdoschedule
+  !DEF: /ompdoschedule/a ObjectEntity REAL(4)
+  !DEF: /ompdoschedule/y ObjectEntity REAL(4)
+  !DEF: /ompdoschedule/z ObjectEntity REAL(4)
+  real  a(100),y(100),z(100)
+  !DEF: /ompdoschedule/b ObjectEntity INTEGER(4)
+  !DEF: /ompdoschedule/i ObjectEntity INTEGER(4)
+  !DEF: /ompdoschedule/n ObjectEntity INTEGER(4)
+  integer  b,i,n
+  !REF: /ompdoschedule/b
+  b = 10
+!$omp do  schedule(static,b-b)
+ !DEF: /ompdoschedule/Block1/i (OmpPrivate, OmpPreDetermined) HostAssoc INTEGER(4)
+ !REF: /ompdoschedule/n
+  do i = 2,n+1
+  !REF: /ompdoschedule/y
+  !REF: /ompdoschedule/Block1/i
+  !REF: /ompdoschedule/z
+  !REF: /ompdoschedule/a
+    y(i) = z(i-1) + a(i)
+  end do
+ !$omp end do
+end program ompdoschedule
diff --git a/flang/test/Semantics/omp-do-schedule04.f90 b/flang/test/Semantics/omp-do-schedule04.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Semantics/omp-do-schedule04.f90
@@ -0,0 +1,32 @@
+! RUN: %S/test_symbols.sh %s %t %f18 -fopenmp
+! OpenMP Version 4.5
+! 2.7.1 Schedule Clause
+! Test that does not catch non constant integer expressions like xx - yy.
+
+  !DEF: /tds (Subroutine) Subprogram
+subroutine tds
+  implicit none
+  !DEF: /tds/a ObjectEntity REAL(4)
+  !DEF: /tds/y ObjectEntity REAL(4)
+  !DEF: /tds/z ObjectEntity REAL(4)
+  real a(100),y(100),z(100)
+  !DEF: /tds/i ObjectEntity INTEGER(4)
+  !DEF: /tds/j ObjectEntity INTEGER(4)
+  !DEF: /tds/k ObjectEntity INTEGER(4)
+  integer i,j,k
+
+  !REF: /tds/j
+  j = 11
+  !REF: /tds/k
+  k = 12
+!$omp do  schedule(static,j-k)
+ !DEF: /tds/Block1/i (OmpPrivate,OmpPreDetermined) HostAssoc INTEGER(4)
+  do i = 1,10
+  !REF: /tds/y
+  !REF: /tds/Block1/i
+  !REF: /tds/z
+  !REF: /tds/a
+    y(i) = z(i-1)+a(i)
+  end do
+ !$omp end do
+end subroutine tds