diff --git a/src/search/providers.py b/src/search/providers.py
index ee16a50..4ec493b 100644
--- a/src/search/providers.py
+++ b/src/search/providers.py
@@ -76,6 +76,56 @@ def _get_result_count() -> int:
         return 5
 
 
+# Canonical SafeSearch levels: "strict" (default), "moderate", "off".
+# Each provider has its own knob name and value space — see _safesearch_for(...).
+_SAFESEARCH_LEVELS = ("strict", "moderate", "off")
+
+
+def _get_safesearch_level() -> str:
+    """Return the configured SafeSearch level, normalized to one of
+    _SAFESEARCH_LEVELS. Defaults to 'strict' to avoid adult / spammy URLs
+    bleeding into research and web_search results."""
+    settings = _get_search_settings()
+    raw = (settings.get("search_safesearch") or "strict").strip().lower()
+    if raw in _SAFESEARCH_LEVELS:
+        return raw
+    # Accept a few common aliases so a manually-edited config doesn't
+    # silently lose SafeSearch — fall back to strict on anything unknown.
+    aliases = {
+        "on": "strict", "high": "strict", "2": "strict",
+        "medium": "moderate", "1": "moderate", "default": "moderate",
+        "none": "off", "disabled": "off", "0": "off",
+    }
+    return aliases.get(raw, "strict")
+
+
+def _safesearch_for(provider: str) -> Optional[str]:
+    """Translate the canonical level into the per-provider param value.
+    Returns None when SafeSearch should be omitted entirely for a provider
+    (some APIs default to filtered and treat missing-param as "off")."""
+    level = _get_safesearch_level()
+    if provider == "searxng":
+        # SearXNG: integer 0/1/2
+        return {"strict": "2", "moderate": "1", "off": "0"}[level]
+    if provider == "brave":
+        # Brave: strict / moderate / off
+        return level
+    if provider == "duckduckgo_lib":
+        # duckduckgo-search library: on / moderate / off
+        return {"strict": "on", "moderate": "moderate", "off": "off"}[level]
+    if provider == "duckduckgo_html":
+        # DDG HTML endpoint kp: 1 strict / -1 moderate / -2 off
+        return {"strict": "1", "moderate": "-1", "off": "-2"}[level]
+    if provider == "google_pse":
+        # Google PSE: 'active' filters explicit; 'off' disables. Treat
+        # moderate the same as active — Google PSE has no middle tier.
+        return None if level == "off" else "active"
+    if provider == "serper":
+        # Serper proxies Google's `safe` param.
+        return None if level == "off" else "active"
+    return None
+
+
 # ── SearXNG ──
 
 _NEWS_HINTS = ("news", "nyheter", "headlines", "breaking", "latest", "today", "idag")
@@ -106,7 +156,8 @@ def searxng_search_api(query: str, count: int = 10, categories: str = "general",
     # Pin English for ALL searches — without it SearXNG mixes languages and
     # brand-ambiguous terms bleed in foreign SEO pages (Honda "Odyssey" JP,
     # Japanese "Trojan" malware blogs, Chinese math forums for "Polyphemus").
-    params = {"q": query, "format": "json", "language": "en"}
+    params = {"q": query, "format": "json", "language": "en",
+              "safesearch": _safesearch_for("searxng")}
     q_lc = query.lower()
     is_news = time_filter is not None or any(h in q_lc for h in _NEWS_HINTS)
     if is_news and categories == "general":
@@ -155,6 +206,7 @@ def searxng_search_api(query: str, count: int = 10, categories: str = "general",
                 "format": "json",
                 "language": "en",
                 "categories": "general",
+                "safesearch": _safesearch_for("searxng"),
             }
             if _GENERAL_ENGINES:
                 fallback["engines"] = _GENERAL_ENGINES
@@ -205,7 +257,7 @@ def searxng_search(query, max_results=10):
     try:
         response = httpx.get(
             f"{instance}/search",
-            params={"q": query},
+            params={"q": query, "safesearch": _safesearch_for("searxng")},
             headers=req_headers,
             timeout=10,
         )
@@ -250,7 +302,8 @@ def _brave_search_impl(query: str, count: int, time_filter: Optional[str] = None
         return []
 
     headers = {"X-Subscription-Token": brave_api_key, "Accept": "application/json"}
-    params = {"q": enhanced_query, "count": count}
+    params = {"q": enhanced_query, "count": count,
+              "safesearch": _safesearch_for("brave")}
     if time_filter:
         time_map = {"day": "day", "week": "week", "month": "month", "year": "year"}
         if time_filter in time_map:
@@ -326,7 +379,7 @@ def duckduckgo_search(query: str, count: int = 10, time_filter: Optional[str] =
         try:
             response = httpx.get(
                 "https://html.duckduckgo.com/html/",
-                params={"q": query},
+                params={"q": query, "kp": _safesearch_for("duckduckgo_html")},
                 headers={"User-Agent": "Mozilla/5.0"},
                 timeout=REQUEST_TIMEOUT,
             )
@@ -365,7 +418,8 @@ def duckduckgo_search(query: str, count: int = 10, time_filter: Optional[str] =
 
     try:
         ddgs = DDGS()
-        raw = ddgs.text(query, max_results=count, timelimit=timelimit)
+        raw = ddgs.text(query, max_results=count, timelimit=timelimit,
+                        safesearch=_safesearch_for("duckduckgo_lib"))
         results = []
         for item in raw:
             url = item.get("href", "")
@@ -407,6 +461,9 @@ def google_pse_search(query: str, count: int = 10, time_filter: Optional[str] =
         "q": query,
         "num": min(count, 10),  # Google PSE max is 10 per request
     }
+    safe = _safesearch_for("google_pse")
+    if safe:
+        params["safe"] = safe
     if time_filter:
         # dateRestrict: d[number], w[number], m[number], y[number]
         time_map = {"day": "d1", "week": "w1", "month": "m1", "year": "y1"}
@@ -511,6 +568,9 @@ def serper_search(query: str, count: int = 10, time_filter: Optional[str] = None
         "q": query,
         "num": count,
     }
+    safe = _safesearch_for("serper")
+    if safe:
+        payload["safe"] = safe
     if time_filter:
         time_map = {"day": "qdr:d", "week": "qdr:w", "month": "qdr:m", "year": "qdr:y"}
         if time_filter in time_map:
diff --git a/src/settings.py b/src/settings.py
index 1172389..b64010e 100644
--- a/src/settings.py
+++ b/src/settings.py
@@ -55,6 +55,26 @@ DEFAULT_SETTINGS = {
     "search_fallback_chain": ["duckduckgo"],
     "search_url": "",
     "search_result_count": 5,
+    # SafeSearch level applied to every provider that exposes one.
+    # "strict"   — block adult / explicit results (default; matches what users
+    #              expect from a research tool and avoids unrelated NSFW URLs
+    #              bleeding in via provider "related" / spam recommendations)
+    # "moderate" — provider-default behavior (filter explicit but allow
+    #              suggestive content)
+    # "off"      — disable filtering entirely (advanced users only)
+    #
+    # Providers that honor this setting (translated to each provider's native
+    # param in src/search/providers.py:_safesearch_for):
+    #     SearXNG       safesearch=0/1/2 (JSON API, HTML scrape, news fallback)
+    #     Brave Search  safesearch=off/moderate/strict
+    #     DuckDuckGo    safesearch=off/moderate/on (library + HTML kp param)
+    #     Google PSE    safe=active (omitted for "off"; PSE has no middle tier)
+    #     Serper.dev    safe=active (omitted for "off"; proxies Google's `safe`)
+    # Providers NOT touched: Tavily (no SafeSearch knob; filters at index time)
+    # and any custom backend reached via search_url — they keep whatever the
+    # backend itself decides, so operators stay in control of self-hosted /
+    # niche search instances.
+    "search_safesearch": "strict",
     "brave_api_key": "",
     "google_pse_key": "",
     "google_pse_cx": "",