diff --git a/docs/releases.rst b/docs/releases.rst
index 182a85764b..a99d30d17a 100644
--- a/docs/releases.rst
+++ b/docs/releases.rst
@@ -24,6 +24,15 @@ discovered tests. This can be useful especially when fetching
 tests from remote repositories where the user does not have write
 access.
 
+The ``tmt reportportal`` plugin has newly introduced size limit
+for logs uploaded to ReportPortal because large logs decreases
+ReportPortal UI usability. Default limit are 1 MB for a test
+output and 50 kB for a traceback (error log).
+Limits can be controlled using the newly introduced
+``reportportal`` plugin options ``-log-size-limit`` and
+``--traceback-size-limit`` or the respective environment
+variables.
+
 
 tmt-1.37.0
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/tmt/schemas/report/reportportal.yaml b/tmt/schemas/report/reportportal.yaml
index fef9cc0a6e..26a47bcfd4 100644
--- a/tmt/schemas/report/reportportal.yaml
+++ b/tmt/schemas/report/reportportal.yaml
@@ -64,6 +64,12 @@ properties:
   api-version:
     type: string
 
+  log-size-limit:
+    type: integer
+
+  traceback-size-limit:
+    type: integer
+
 required:
   - how
   - project
diff --git a/tmt/steps/report/reportportal.py b/tmt/steps/report/reportportal.py
index 91d0c2f5d6..b6ff3905a4 100644
--- a/tmt/steps/report/reportportal.py
+++ b/tmt/steps/report/reportportal.py
@@ -15,6 +15,8 @@
     from tmt._compat.typing import TypeAlias
 
 JSON: 'TypeAlias' = Any
+DEFAULT_LOG_SIZE_LIMIT: int = 1024 * 1024
+DEFAULT_TRACEBACK_SIZE_LIMIT: int = 50 * 1024
 
 
 def _flag_env_to_default(option: str, default: bool) -> bool:
@@ -41,13 +43,56 @@ def _str_env_to_default(option: str, default: Optional[str]) -> Optional[str]:
     return str(os.getenv(env_var))
 
 
-def _filter_invalid_chars(data: str) -> str:
+class LogFilterSettings:
+    size: int
+    is_traceback: bool
+
+    def __init__(self,
+                 size: int = DEFAULT_LOG_SIZE_LIMIT,
+                 is_traceback: bool = False):
+        self.size = size
+        self.is_traceback = is_traceback
+
+
+def _filter_invalid_chars(data: str,
+                          settings: LogFilterSettings) -> str:
     return re.sub(
         '[^\u0020-\uD7FF\u0009\u000A\u000D\uE000-\uFFFD\U00010000-\U0010FFFF]+',
         '',
         data)
 
 
+def _filter_log_per_size(data: str,
+                         settings: LogFilterSettings) -> str:
+    size = len(data)
+    if settings.is_traceback:
+        variable = "TMT_PLUGIN_REPORT_REPORTPORTAL_LOG_SIZE_LIMIT"
+        option = "--traceback-size-limit"
+    else:
+        variable = "TMT_PLUGIN_REPORT_REPORTPORTAL_LOG_SIZE_LIMIT"
+        option = "--log-size-limit"
+    header = (f"WARNING: Uploaded log has been truncated because its size {size} bytes "
+              f"exceeds tmt reportportal plugin limit of {settings.size} bytes."
+              f"The limit is controlled with {option} plugin option or"
+              f"{variable} environment variable.\n\n")
+    if size > settings.size:
+        return f"{header}{data[:settings.size]}"
+    return data
+
+
+_LOG_FILTERS = [
+    _filter_log_per_size,
+    _filter_invalid_chars,
+    ]
+
+
+def _filter_log(log: str, settings: Optional[LogFilterSettings] = None) -> str:
+    settings = settings or LogFilterSettings()
+    for log_filter in _LOG_FILTERS:
+        log = log_filter(log, settings=settings)
+    return log
+
+
 @dataclasses.dataclass
 class ReportReportPortalData(tmt.steps.report.ReportStepData):
 
@@ -142,6 +187,28 @@ class ReportReportPortalData(tmt.steps.report.ReportStepData):
              (e.g. 'Idle'). 'To Investigate' is used by default.
              """)
 
+    log_size_limit: int = field(
+        option="--log-size-limit",
+        metavar="LOG_SIZE_LIMIT",
+        default=int(
+            _str_env_to_default('log_size_limit', str(DEFAULT_LOG_SIZE_LIMIT))),
+        help=f"""
+              Size limit in bytes for log upload to ReportPortal.
+              The default limit is {DEFAULT_LOG_SIZE_LIMIT} bytes
+              ({DEFAULT_LOG_SIZE_LIMIT / 1024 / 1024} MB).
+              """)
+
+    traceback_size_limit: int = field(
+        option="--traceback-size-limit",
+        metavar="TRACEBACK_SIZE_LIMIT",
+        default=int(
+            _str_env_to_default('traceback_size_limit', str(DEFAULT_TRACEBACK_SIZE_LIMIT))),
+        help=f"""
+              Size limit in bytes for traceback log upload to ReportPortal.
+              The default limit is {DEFAULT_TRACEBACK_SIZE_LIMIT} bytes
+              ({DEFAULT_TRACEBACK_SIZE_LIMIT / 1024} kB).
+              """)
+
     exclude_variables: str = field(
         option="--exclude-variables",
         metavar="PATTERN",
@@ -595,10 +662,16 @@ def go(self, *, logger: Optional[tmt.log.Logger] = None) -> None:
                         status = self.TMT_TO_RP_RESULT_STATUS[result.result]
 
                         # Upload log
+
+                        message = _filter_log(log,
+                                              settings=LogFilterSettings(
+                                                  size=self.data.log_size_limit
+                                                  )
+                                              )
                         response = self.rp_api_post(
                             session=session,
                             path="log/entry",
-                            json={"message": _filter_invalid_chars(log),
+                            json={"message": message,
                                   "itemUuid": item_uuid,
                                   "launchUuid": launch_uuid,
                                   "level": level,
@@ -606,7 +679,12 @@ def go(self, *, logger: Optional[tmt.log.Logger] = None) -> None:
 
                         # Write out failures
                         if index == 0 and status == "FAILED":
-                            message = _filter_invalid_chars(result.failures(log))
+                            message = _filter_log(result.failures(log),
+                                                  settings=LogFilterSettings(
+                                                      size=self.data.traceback_size_limit,
+                                                      is_traceback=True
+                                                      )
+                                                  )
                             response = self.rp_api_post(
                                 session=session,
                                 path="log/entry",