Short answer
Settings > Marketing > Ads > Ad accounts > Connect account > Reddit Ads. Log in to Reddit, review the permissions, and click Continue. HubSpot says it needs all of the requested permissions. Once connected, Reddit campaign reporting sits next to your other ad channels, contacts and deals can be attributed to Reddit campaigns, and contacts who interact with the ads can be enrolled in workflows. The KB lists the integration as a beta.
1. Where it is
My demo portal has no ad accounts yet. The ads settings page shows Reddit among the supported networks.

2. After connecting
- Campaign reporting with your other ad networks.
- Contacts and deals attributed to Reddit campaigns.
- Workflow enrollment for contacts who interact with the ads.
3. Managing it
Hover the account and use Actions to view details such as auto-tracking and primary users, or connect a Reddit user if none is linked. Reddit as a social publishing channel is a separate connection. See connecting social accounts and connecting ad accounts.