The Top 150-listed agency first put on the week of free events in 2015, at the time when a major cyber attack on TalkTalk was grabbing headlines.
The agency's founder Yvonne Eskenzi said at the time that she was putting on the week due to a lack of publicity for European Cyber Security Month, the EU-led campaign that takes place each October.
This year, Security Serious Week includes five webinars each day from Monday onwards, starting with one on the global shortfall in cyber security talent, which will be a theme running through the rest of the week's events.
On Tuesday (3 October), Eskenzi is hosting the Security Serious Unsung Heroes Awards in central London. The awards are free to enter and attend.
Eskenzi said: "Security Serious Week has been set up as our contribution to European Cyber Security Awareness Month and we’ve made the skills shortage the main focus of the week. Threats are coming at UK businesses from all angles and there are simply not enough people to defend against them.
"What we want to do is shout about how amazing our industry is and bring in new blood by explaining you don’t have to be a techie genius; there are many skills that are needed in cyber security, including communication skills, management, marketing, coding, sales – you certainly don’t need a degree or conventional qualifications to succeed in our profession."