Background: Zimbabwe’s agricultural sector faces an imminent threat from 73 invasive plant pests currently established in neighbouring countries, with the highest risk of entry stemming from travellers and their luggage, a new horizon scan reveals. Methods: The Centre for Agriculture and Bioscience International (CABI) Horizon Scanning Tool (HST), one of the modules used to focus pest threats for specific geographical areas, was employed to scan threats to Zimbabwe’s plant biosecurity. The likelihood of pest entry and establishment was determined using the procedure for pest risk analysis described by CABI and Food and Agriculture Organisation. The European and Mediterranean Plant Protection Organization method for likelihood of entry and the likelihood of establishment were ranked on a scale of 1 (very unlikely) to 5 (very likely). Pest rating was done by the selected pest risk analysis experts from the Plant Health Authorities in Zimbabwe. Descriptive statistics were mostly used to analyse the threats. Diversity indices were included to bring a new dimension to pest risk analysis where these indices capture meaningful ecological patterns relevant to threats of invasive pest inversion to the country. Results: There were 29 plant pests, 58 invertebrates, 17 fungi/chromista, 4 bacteria, 5 viruses, and one vertebrate pest-threat species recorded in Zimbabwe’s neighbours, whilst 1,163 pest threats were present in SADC and 16,651 were found globally. The HST revealed more invertebrate pest threat organisms to Zimbabwe’s plant biosecurity than the other pest organisms. Zimbabwe’s neighbours had 50% invertebrate threats; SADC had 43% whilst the global scan revealed 47%. More threats were from South Africa (87%) than the other three neighbours (13%). Of the identified pest threats from the Zimbabwe’s four neighbours, 73 (64%) pest species had entry and establishment score of 3 (moderately likely or more). These 73 pest species comprised of 3 (4%) bacteria, 9 (12%) fungi, 46 (63%) invertebrates, 11 (15%) weeds/plants, and 4 (5%) viruses. Of the identified pest threats from the Zimbabwe’s four neighbours, 73 (64%) pest species had entry and establishment score of 3 (moderately likely or more). These 73 pest species comprised of 3 (4%) bacteria, 9 (12%) fungi, 46 (63%) invertebrates, 11 (15%) weeds/plants, and 4 (5%) viruses. Dysmicoccus brevipes (score 5), Polyphagotarsonemus latus (4), Aleurothrixus floccosus (4), Aonidiella orientalis (4), Ceratitis rosa (4), Phoracantha recurva (4), Erysiphe platani, Fusarium oxysporum f. sp. cubense (4), Candidatus phytoplasma palmae (4), Amaranthus retroflexus (4), Solanum torvum (4), and Maize Chlorotic Mottle Virus (4) were amongst the major threats Zimbabwe’s plant biosecurity faces. Simpson diversity index revealed that Zimbabwe’s neighbours had moderate pest threat diversity (1-D = 0.62). The invertebrates (51%), dominated the pest threats present in the neighbours. SADC (1-D = 0.66) had higher diversity with plants (40%) and invertebrates (43%). The Shannon diversity index (H′) revealed a gradient pattern where global diversity (H′ = 1.63) was the highest, then SADC (H′ = 1.41), and lastly, the Zimbabwe’s neighbours (H′ = 1.37). Conclusions: This study provides the first systematic horizon scan and prioritization of invasive pest threats for Zimbabwe, offering a critical evidence base for proactive biosecurity policy and resource allocation.