diff --git a/contrib/pg_upgrade/tablespace.c b/contrib/pg_upgrade/tablespace.c
index 4086e53cf56dacf7ac73a80f56a03663a60129b2..d7276cdb437308242b87e4fd382e2f53422911be 100644
--- a/contrib/pg_upgrade/tablespace.c
+++ b/contrib/pg_upgrade/tablespace.c
@@ -36,7 +36,7 @@ init_tablespaces(void)
  * get_tablespace_paths()
  *
  * Scans pg_tablespace and returns a malloc'ed array of all tablespace
- * paths. Its the caller's responsibility to free the array.
+ * paths. It's the caller's responsibility to free the array.
  */
 static void
 get_tablespace_paths(void)
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index b1c411a0b9665366d00c208437cec5e629123f6c..80d3728e08bb8879cee23ceb17b36f28a773e41e 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1518,7 +1518,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 	 * swap_relation_files()), thus relfrozenxid was not updated. That's
 	 * annoying because a potential reason for doing a VACUUM FULL is a
 	 * imminent or actual anti-wraparound shutdown.  So, now that we can
-	 * access the new relation using it's indices, update relfrozenxid.
+	 * access the new relation using its indices, update relfrozenxid.
 	 * pg_class doesn't have a toast relation, so we don't need to update the
 	 * corresponding toast relation. Not that there's little point moving all
 	 * relfrozenxid updates here since swap_relation_files() needs to write to
diff --git a/src/interfaces/ecpg/ecpglib/execute.c b/src/interfaces/ecpg/ecpglib/execute.c
index 993cb49d74c34adbabb34f2f9ee060c3d1978cb2..f6cc33c31447d7491bebb1bc482b69bd74ca7d39 100644
--- a/src/interfaces/ecpg/ecpglib/execute.c
+++ b/src/interfaces/ecpg/ecpglib/execute.c
@@ -1304,8 +1304,8 @@ ecpg_build_params(struct statement * stmt)
 		if ((position = next_insert(stmt->command, position, stmt->questionmarks, std_strings) + 1) == 0)
 		{
 			/*
-			 * We have an argument but we dont have the matched up placeholder
-			 * in the string
+			 * We have an argument but we don't have the matched up
+			 * placeholder in the string
 			 */
 			ecpg_raise(stmt->lineno, ECPG_TOO_MANY_ARGUMENTS,
 					   ECPG_SQLSTATE_USING_CLAUSE_DOES_NOT_MATCH_PARAMETERS,
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index ea46a1aeca1cdc034c030391bc629f7eb5168f59..03bab07aeaa00e250190f98f60336d65071603e7 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -2337,7 +2337,7 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
 	}
 
 	/************************************************************
-	 * If there was a argtype list on preparation, we need
+	 * If there was an argtype list on preparation, we need
 	 * an argument value list now
 	 ************************************************************/
 	if (qdesc->nargs > 0)